The triangular side walls of a flyover have been used for advertisements. The sides of the walls are 122 m, 22 m, and 120 m (see Fig. 12.9). The advertisements yield an earning of ₹ 5000 per m2 per year. A company hired one of its walls for 3 months. How much rent did it pay?
Solution:
Given: Dimensions of the triangular sides of walls.
By using Heron’s formula, we can calculate the area of triangle.
Heron's formula for the area of a triangle is: Area = √s(s - a)(s - b)(s - c)
Where a, b and c are the sides of the triangle, and s = Semi-perimeter = Half the Perimeter of the triangle
Triangular sides of walls are, a = 122 m, b = 22 m, c = 120 m
Semi Perimeter, s = (a + b + c)/2
= (122 + 22 + 120)/2
= 264/2
= 132 m
By using Heron’s formula,
Area of a triangle = √s(s - a)(s - b)(s - c)
Substuting the values in order to find area of triangular wall,
= √132(132 - 122) (132 - 22) (132 - 120)
= √132 × 10 × 110 × 12
= 1320 m
Rent of 1 m2 area per year = ₹ 5000
Rent of 1 m2 area per month = ₹ 5000/12
Rent of 1320 m2 area for 3 months = ₹ (5000/12) × 3 × 1320
= ₹ 1650000
Therefore, the company paid ₹ 16,50,000 as rent.
☛ Check: NCERT Solutions for Class 9 Maths Chapter 12
Video Solution:
The triangular side walls of a flyover have been used for advertisements. The sides of the walls are 122 m, 22 m, and 120 m (see Fig. 12.9). The advertisements yield an earning of ₹ 5000 per sq. m per year. A company hired one of its walls for 3 months. How much rent did it pay?
Class 9 Maths NCERT Solutions Chapter 12 Exercise 12.1 Question 2
Summary:
It is given that the triangular side walls of a flyover have been used for advertisements. The sides of the walls are 122 m, 22 m, and 120 m. The advertisements yield an earning of ₹ 5000 per m2 per year. A company hired one of its walls for 3 months. Therefore, the company paid ₹ 16,50,000 as rent.
☛ Related Questions:
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- Find the area of a triangle two sides of which are 18cm and 10cm and the perimeter is 42cm.
- Sides of a triangle are in the ratio of 12:17:25 and its perimeter is 540cm. Find its area.
- An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of the triangle.
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