Ex 12.1, 2
The triangular side walls of a flyover have been used for advertisements. The sides of the walls are 122m, 22m, and 120m. The advertisements yield an earning of Rs 5000 per m2 per year. A company hired one of its walls for 3 months. How much rent did it pay?
Area of triangle = √(𝑠(𝑠 −𝑎)(𝑠 −𝑏)(𝑠 −𝑐))
Putting a = 122 m, b = 22 m , c = 120 m , s = 122 m
Area = √(132(132−122)(132−22)(132−120)) m2
= √(132×(10)×(110)×(12) )m2
= √(132×11×12×(102) )m2
= √((132×132)×(102) )m2
= √((132)2×(102) )m2
= √((132)2) √((102) ) m2
= 〖(1322)〗^(1/2) × 〖(102)〗^(1/2)
= 132 × 10
Rent of 1 m2 area per year = Rs 5000
Rent of 1 m2 area per month = Rs 5000/12
Rent of 1 m2 area per 3month = Rs 5000/12 ×3
Rent of 1320 m2 area for 3 months
= Rs (5000 × 330)
Therefore, the company had to pay Rs 1650000.

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.