Q1. A triangular grassy park, with side lengths 11 m, 6 m, and 15 m, has the message “KEEP THE PARK GREEN AND CLEAN” written on it. What is the semi-perimeter of the park?
16m
Show Answer
Q2. What is Heron’s Formula used for?
Finding the area of a triangle.
Show Answer
Q3. A traffic signal board, indicating ‘SCHOOL AHEAD’, is an equilateral triangle with side ‘60 cm’. What is the perimeter of the signal board.
180
Show Answer
Q4. The area of a triangular wall used for advertisement is 1320 m². The rate is ₹5000 per m² per year. A company hires it for 3 months. What is the rent paid?
A₹6,60,000
B₹13,20,000
C₹16,50,000
D₹19,80,000
Q5. A triangular field ABC has sides 120 m, 80 m, and 50 m. Find the cost of fencing it with barbed wire at the rate of ₹20 per metre, leaving a 3 m space for a gate on one side.
₹4940
Show Answer
Q6. Who derived the formula to find the area of a triangle in terms of its three sides?
Heron
Show Answer
Q7. If the area of the triangle using the formula: \( \frac{1}{2} \) x base x height is 100 \( m^2 \), what will be the area of the triangle using the Heron's formula?
A50 \(m^2 \)
B100 \(m^2 \)
C1000 \(m^2 \)
D10000 \(m^2 \)
Q8. One side of an equilateral triangle is "a". What is the semi-perimeter of the triangle?
\( \frac{3a}{2} \)
Show Answer
Q9. Area of equilateral triangle of side 'a' unit is
A\( \frac{\sqrt{3}}{2} \) \( a^2 \)
B\( \frac{\sqrt{3}}{4} \) \( a^2 \)
C\( \frac{\sqrt{3}}{2} \) a
Dnone of these
Q10. The area of an equilateral triangle is 9\(\text{} \sqrt{3} \) \( cm^2 \). What is the perimeter of the triangle?
18 cm
Show Answer
Q11. If the area of an equilateral triangle is 100 \(\text{} \sqrt{3} \) \( cm^2 \), then what is its side?
A20 \(\text{} \sqrt{3} \) cm
B20 cm
C10 \(\text{} \sqrt{3} \) cm
D5 cm
Q12. The length of altitude of an equilateral triangle of side 'a' unit is
A\( \frac{\sqrt{3}}{2} \) \( a^2 \)
B\( \frac{\sqrt{3}}{4} \) \( a^2\)
C\( \frac{\sqrt{3}}{2} \) a
D\( \frac{\sqrt{3}}{4} \) a
Q13. The area of an equilateral triangle is 16 \( \sqrt{3} \) \( cm^2 \). Find the semi-perimeter of the triangle.
12 cm
Show Answer
Q14. The sides of a triangle are 32 m, 24 m, and 40 m. What is the semi-perimeter of the triangle?
48 m
Show Answer
Q15. What is the area of an equilateral triangle of side 2 cm?
\( \sqrt{3} \) \( cm^2 \)
Show Answer
Q16. In the given figure, the base and height of the triangle are given. Calculate the area of the triangle.
12 \( cm^2 \)
Show Answer
Q17. What is the length of the hypotenuse in the given figure?
5 cm
Show Answer
Q18. The base of a triangle is 12 cm and height is 8 cm, then the area of a triangle is:
A24 \(cm^2 \)
B96 \( cm^2 \)
C48 \( cm^2 \)
D56 \( cm^2 \)
Q19. In the given figure, a triangle has sides 3 cm, 4 cm, and 5 cm. Find its area.
6 \( cm^2 \)
Show Answer
Q20. Find the area of a right-angled triangle whose perpendicular sides measure 20 cm and 15 cm.
150 \( cm^2 \)
Show Answer
Q21. A triangle and a parallelogram have the same base and the same area. If the area of the triangle is 336 cm² and the parallelogram stands on a base 28 cm, then what is the height of the parallelogram?
A12 cm
B24 cm
C6 cm
D48 cm
Q22. The height of an equilateral triangle is 6 cm. Find its side?
A\(\text{ } \sqrt{3} \) cm
B2\(\text{ }\sqrt{3} \) cm
C3\(\text{ }\sqrt{3} \) cm
D4\(\text{ }\sqrt{3} \) cm
Q23. An isosceles triangle has a perimeter of 30 cm, and each of its equal sides measures 12 cm. Find the length of the third side.
A24 cm
B15 cm
C6 cm
D12 cm
Q24. In a right-angled triangle ABC, AB = 5 cm, AC = 12 cm, and BC = 13 cm. What is the area of Δ ABC?
30 \( cm^2 \)
Show Answer
Q25. Δ XYZ is isosceles with XY = XZ = 5 cm and YZ = 8 cm. Calculate the area of Δ XYZ.
12 \( cm^2 \)
Show Answer
Q26. Which of the following is the correct form of Heron’s formula?
A\( \sqrt{s(a−s)(b−s)(c−s)} \)
B\( \sqrt{2s(s−a)(s−b)(s−c)} \)
C\( \sqrt{s(s−a)(s−b)(s−c)} \)
D\( \sqrt{2s(a−s)(b−s)(c−s)} \)
Q27. The given figure shows an equilateral triangle with a side of 10 cm. Which of the following is its area?
A10 \(\sqrt{3} \) \( cm^2 \)
B100 \(\sqrt{3} \) \( cm^2 \)
C5 \(\sqrt{3} \) \( cm^2 \)
D25 \(\sqrt{3} \) \( cm^2 \)
Q28. Two sides of a triangle measure 8 cm and 11 cm, and the perimeter is 32 cm. Find the length of the third side.
13 cm
Show Answer
Q29. A triangular park has sides measuring 100 m, 75 m, and 65 m. A gardener plans to put a wire fence all around the park, leaving a gap of 4 m on one side for a gate. What is the total length of wire required for fencing?
236 m
Show Answer
Q30. An isosceles triangle has a perimeter of 30 cm and a base of 6 cm. Find the length of each of the equal sides.
12 cm
Show Answer
Q31. The semi-perimeter (s) of triangle with sides 40 m, 24 m, and 32 m is:
A48 m
B96 m
C56 m
D24 m
Q32. The semi-perimeter of a triangle is 48 m. The value of s−a, where a=40 m, is:
A16 m
B8 m
C24 m
D12 m
Q33. A triangle has sides measuring 40 m, 24 m, and 32 m. What is the value of s−b, where b = 24 m?
A8 m
B16 m
C12 m
D24 m
Q34. The semi-perimeter(s) of a triangle is 48 m. The value of s−c, where c=32 m, is
A8 m
B24 m
C16 m
D48 m
Q35. The sides of a triangular park ABC are 40 m, 24 m, and 32 m. It is observed that \( 32^2 \) + \( 24^2 \) = \( 40^2 \). Based on this information, what type of triangle is formed by the park?
Right-angled triangle
Show Answer
Q36. The perimeter of a triangle is 90 cm and its sides are in the ratio 2 : 3 : 4. Which of the following is the smallest side?
A5 cm
B10 cm
C15 cm
D20 cm
Q37. The three sides of a triangle are 6 cm, 8 cm, and 10 cm. What is the area of the triangle?
24 \( cm^2 \)
Show Answer
Q38. The sides of a triangle are in the ratio 3 : 4: 5 and the perimeter is 60 cm. What is the area of the triangle?
150 \( cm^2 \)
Show Answer
Q39. A traffic signal board indicating "GO SLOW" is an equilateral triangle with side 80 cm. What is the area of the signal board?
A800\(\sqrt{3} \) \( cm^2 \)
B1600\(\sqrt{3} \) \( cm^2 \)
C2400\(\sqrt{3} \) \( cm^2 \)
D400\(\sqrt{3} \) \( cm^2 \)
Q40. Find the area of a right triangle in which the sides containing the right angle measure 20 cm and 14 cm.
140 \( cm^2 \)
Show Answer
Q41. A triangular signboard displays the message “QUIT SMOKING.” The lengths of its sides are 30 cm, 40 cm, and 50 cm. Find the area of the signboard.
600 \( cm^2 \)
Show Answer
Q42. The perimeter of a triangular field is 420 m, and its sides are in the ratio 6 : 7 : 8. Which of the following represents the lengths of its sides?
A120 m, 140 m, 160 m
B100 m, 120 m, 200 m
C90 m, 140 m, 190 m
D110 m, 130 m, 180 m
Q43. A craftsman is decorating a triangular board with sides 6 cm, 8 cm, and 10 cm. He wants to cover all its edges with tape. What is the total length of tape needed?
24 cm
Show Answer
Q44. A farmer owns a field in the shape of a parallelogram with sides 60 m and 40 m. A diagonal of length 80 m divides the field into two triangular regions. If the area of one triangular region is 300 \(\sqrt{3} \) \( m^2 \), what is the total area of the field?
600 \(\sqrt{3} \) \( m^2 \)
Show Answer
Q45. The sides of the triangular field are 50 m, 65 m, and 65 m, and its area is 1500 \( m^2 \). If the cost of laying grass is ₹7 per \( m^2 \), find the total cost of covering the field with grass.
₹10,500
Show Answer
Q46. If the sides of a triangle are a, b, and c, which of the following represents its semi-perimeter(s)?
Aa + b + c
B2(a + b + c)
C\( \frac{a + b + c}{2} \)
D\( \frac{a + b + c}{3} \)
Q47. The perimeter of an equilateral triangle is 24 cm. What is its area?
A12 \(\sqrt{3} \) \( m^2 \)
B16 \(\sqrt{3} \) \( m^2 \)
C8 \(\sqrt{3} \) \( m^2 \)
D64 \(\sqrt{3} \) \( m^2 \)
Q48. The semi-perimeter of a triangle having the length of its sides as 20cm, 15cm and 9 cm is
A44 cm
B21 cm
C22 cm
D12 cm
Q49. The area of a triangle is 48 \( cm^2 \). If its base is 12 cm, find its altitude.
8 cm
Show Answer
Q50. An isosceles right triangle has area 8 \( cm^2 \). Find the length of each side.
4 cm
Show Answer
Q51. Find the area of an isosceles triangle having base 2 cm and length of its equal side 4 cm.
\(\sqrt{15} \)
Show Answer
Q52. The sides of a triangle are 6 cm, 8 cm, and 10 cm. Which statement is correct?
AThe triangle is equilateral
BThe triangle is obtuse-angled
CThe triangle is right-angled
DThe triangle is isosceles
Q53. The perimeter of a triangle is 300 m, and its sides are in the ratio 3:5:7. What is the length of the smallest side?
60 m
Show Answer
Q54. A park has sides measuring 24 m, 32 m, and 40 m. What type of triangle is formed by the park?
A right-angled triangle
Show Answer
Q55. The perimeter of a triangular field is 540 m, and its sides are in the ratio 12:17:25. If the cost of fencing is ₹30 per metre, what is the total cost of fencing the field?
₹16,200
Show Answer
Q56. An isosceles right triangle has area 8 \( cm^2 \). What is the length of its hypotenuse?
4\(\sqrt{2} \) cm
Show Answer
Q57. The sides of a triangle are 14 cm, 21 cm, and 35 cm. Find the ratio of its sides in the simplest form.
2 : 3 : 5
Show Answer
Q58. A gardener wants to prepare rose beds in a triangular garden whose sides measure 15 m, 8 m, and 17 m. If each rose bed, on average, requires 4 m² of space, find the number of rose beds that can be prepared in the garden.
15
Show Answer
Q59. The sides of a triangle are 9 cm, 12 cm, and 15 cm. Which of the following sides is the hypotenuse of the triangle?
A9 cm
B12 cm
C15 cm
D21 cm
Q60. A triangle whose sides measure 12 cm, 16 cm, and 20 cm is divided into square sections of area 8 \( cm^2 \) each. What is the maximum number of sections that can be made?
12
Show Answer
Q61. The perimeter of a triangular field is 420 m and its sides are in the ratio 6:7:8. Calculate the length of each side of the field.
120 m, 140 m, and 160 m
Show Answer
Q62. A farmer has a triangular field with a total boundary length of 360 m. He wants to fence the entire field. The fencing company charges ₹55 per metre for fencing. Help the farmer find the total amount he must pay.
₹19,800
Show Answer
Q63. The sides of a triangle are 4x, 6x, and 9x, and its perimeter is 380 cm. Find the value of x.
20
Show Answer
Q64. One leg of a right triangle is 5 cm and the hypotenuse is 13 cm. What is the area of the triangle?
30 \( cm^2 \)
Show Answer
Q65. The area of a triangular wall used for advertisement is 600 m². The advertising rate is ₹50 per m² per month. Find the total rent to be paid for one month.
₹30,000
Show Answer
Q66. The perimeter of an equilateral triangle is 60m. Then its area is
A10\( \sqrt{3} \)\( m^2 \)
B15\( \sqrt{3} \)\( m^2 \)
C20\( \sqrt{3} \)\( m^2 \)
D100\( \sqrt{3} \)\( m^2 \)
Q67. Assertion (A): The area calculated using Heron's formula is always positive.
Reason (R): The area obtained from Heron's formula is always an integer.
ABoth A and R are true and R is the correct explanation of A
BBoth A and R are true but R is not the correct explanation of A
CA is true, but R is false
DA is false but R is true
Q68. Assertion (A): If the semi-perimeter of a triangle is equal to the length of one of its side, the the area of a triangle is zero.
Reason (R): This is because the triangle collapses into a straight line.
ABoth A and R are true and R is the correct explanation of A
BBoth A and R are true but R is not the correct explanation of A
CA is true, but R is false
DA is false but R is true
Q69. The sides of a triangle are a, b, and c. If each side is doubled, then what will be the correct expression for the semi-perimeter of the new triangle?
Aa+b+c
B2(a+b+c)
C\(\frac{(a+b+c)}{2} \)
D\(\frac{(a+b+c)}{4} \)
Q70. The area of a triangle with sides a, b, and c is given by \(\sqrt{s(s−a)(s−b)(s−c)} \). If each side is doubled, then which of the following is the correct formula for the area of the new triangle
A\(\sqrt{s(s−a)(s−b)(s−c)} \)
B2\(\sqrt{s(s−a)(s−b)(s−c)} \)
C4\(\sqrt{s(s−a)(s−b)(s−c)} \)
D\(\frac{1}{2} \) \(\sqrt{s(s−a)(s−b)(s−c)} \)
Q71. In the given figure, the area of triangle ABC is 84 \( cm^2 \). What is the area of the shaded region ACBD?
54 \( cm^2 \)
Show Answer
Q72. A scenery in the form of an equilateral triangle is displayed on the wall of a room. Its sides measure 40 cm each. What is the area of the scenery?
400 \(\sqrt{3} \) \( cm^2 \)
Show Answer
Q73. A person purchased a plot of land and divided the land into three parts: a warehouse, an inventory section, and a canteen, as shown in the figure. Find the cost of tiling the canteen floor at the rate of ₹500 per \( m^2 \).
Cost = ₹3000
Show Answer
Q74. In the given figure, △ABC is an equilateral triangle with each side equal to a. Which of the following represents the area of △ABC?
A\(\frac{3}{4} \) \( a^2 \)
B\(\frac{\sqrt{3} }{4} \) \( a^2 \)
C\(\frac{\sqrt{3} }{2} \) \( a^2 \)
D\(\frac{3}{2} \) \( a^2 \)
Q75. For the Annual Day function of the school, 200 triangular flags of sides 25 cm, 25 cm, and 14 cm were to be prepared. If the area of one flag is 168 \( cm^2 \), how much cloth will be required for all the flags in \( m^2 \)?
3.36 \( m^2 \)
Show Answer
Q76. The area of an isosceles triangle with sides 17 cm,17 cm and 30 cm is
A289\( cm^2 \)
B240\( cm^2 \)
C60\( cm^2 \)
D120\( cm^2 \)
Q77. Number of times area changed when sides of a triangle are doubled is
ADouble
BFour times
CEight times
DNo change in the area
Q78. Find the area of the triangle whose sides are 20 cm, 16 cm and 12 cm.
96\( cm^2 \)
Show Answer
Q79. Find the area of a rhombus whose side is 10 cm and one diagonal is 12 cm.
96\( cm^2 \)
Show Answer
Q80. The perimeter of an isosceles triangle is 32 cm. The ratio of equal side to the base is 3:2. Using Heron’s formula, find the area of triangle.
32\( \sqrt{2} \)\( cm^2 \)
Show Answer
Q81. Two adjacent sides of a parallelogram measures 5 cm and 3.5 cm. One of its diagonal measures 6.5 cm. Find the area of the triangle ACD.
5\( \sqrt{3} \)\( cm^2 \)
Show Answer
Q82. Find the area of the triangle ADB in the figure given below.
96\( cm^2 \)
Show Answer
Q83. The perimeter of a triangle is 50 cm. One side of the triangle is 4 cm longer than the smallest side and the third side is 20 cm. Find the area of the triangle.
20\( \sqrt{30} \)\( cm^2 \)
Show Answer
Q84. The length of the perpendicular drawn on the longest side of a scalene triangle is
Alargest
Bsmallest
Cno relation
Dnone of these
Q85. Semi - perimeter of the scalene triangle of side k, 2k, 3k is
Ak
B2k
C3k
Dnone of these
Q86. Find the area of a triangle whose sides are respectively 9 cm, 12 cm and 15 cm.
54\( cm^2 \)
Show Answer
Q87. A park in the shape of a quadrilateral ABCD has ∠ C = \( 90^0 \), AB = 9 m, BC = 12 m, CD = 5 m, AD = 8 m. Find the area of the triangle ABD
6\( \sqrt{35} \)\( m^2 \)
Show Answer
Q88. Find the area of an isosceles triangle having the base x cm and one side y cm.
\( \frac{x}{4} \)\( \sqrt{4y^2-x^2} \)
Show Answer
Q89. The perimeter of a given triangle is 30 cm. The sides are in the ratio 1: 3: 2, then its smallest side is:
A15 cm
B10 cm
C1 cm
D5 cm
Q90. Find the area of an isosceles triangle with two equal sides as 5 cm each and the third side as 8 cm.
12\( cm^2 \)
Show Answer