Book: RS Aggarwal & V Aggarwal - Mathematics
Chapter: 7. Areas
Subject: Mathematics - Class 9th
Q. No. 32 of CCE Questions
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A floral design on a floor is made up of 16 triangular tiles, each having sides 9cm, 28 cm and 35 cm. Find the cost of polishing the tiles at the rate of Rs. 2.50 per cm2
[Take 
=2.454]
Let the sides of triangle be 9 cm, 28 cm, and 35 cm
Semi perimeter, 
Now, using Heron’s formula,
(Area of 1 tile)
= 88.2cm2
∴ Area of 16 tiles = 16 × area of one tile
= 16 × 88.2 cm2
= 1411.2 cm2
Now, cost of polishing 1cm2 area = Rs 2.5
∴ Cost of polishing 1411.2 cm2 = 2.5 × 1411.2 = Rs 3528
Chapter Exercises
More Exercise Questions
cm2. Its perimeter is –
cm2. Its height is-
a2
)a
The question consists of two statements namely, Assertion (a) and Reason (R). Please select the correct answer.
Assertion (A) | Reason (R) |
Area of an equilateral triangle having each side equal to 4cm is | Area of an equilateral triangle having each side a is |
sq cm.
a2 sq units.The question consists of two statements namely, Assertion (a) and Reason (R). Please select the correct answer.
Assertion(A) | Reason (R) |
The area of an isosceles triangle having base = 8cm and each of the equal sides = 5cm is 12cm2. | The area of an isosceles triangle having each of the equal sides as a and base =b is |
.The question consists of two statements namely, Assertion (a) and Reason (R). Please select the correct answer.
Assertion(A) | Reason (R) |
The area of an equilateral triangle having side 4cm is 3cm2 | The area of an equilateral triangle having each side a is ( |
a2) sq units.The question consists of two statements namely, Assertion (a) and Reason (R). Please select the correct answer.
Assertion (A) | Reason (R) |
The sides of the triangle ABC are in the ratio 2 : 3 : 4 and its perimeter is 36 cm. Then ar(Δ ABC) = | If 2s = (a + b +c) where a, b, c are the sides of the triangle, then its area is = |
cm2.
.The question consists of two statements namely, Assertion (a) and Reason (R). Please select the correct answer.
Assertion (A) | Reason (R) |
The area of an isosceles triangle having base = 24 cm and each of the equal sides equal to 13cm is 60cm2. | If 2s = (a + b+ c) where a, b, c are the sides of a triangle, then area = |
.
cm2.Match the following columns.
Column I | Column II |
(a) The lengths of three sides of a triangle are 26 cm, 28 cm and 30cm. The height corresponding to base 28cm is……cm | (p) 6 |
(b) The area of an equilateral triangle is | (q) 4 |
(c) If the height of an equilateral triangle is | (r) 24 |
(d) Let the base of an isosceles triangle be 6 cm and each of the equal side be 5cm. Then, its height is ….cm | (s) 12 |
cm2. The perimeter of the triangle is…..cm
cm, then each side of the triangle measures …. CmThe correct answer is :
(a)-…….. (b)-……..
(c)-……… (d)-………
= 5.9]
= 3.87]
= 2.24]
