Book: RS Aggarwal & V Aggarwal - Mathematics
Chapter: 7. Areas
Subject: Mathematics - Class 9th
Q. No. 2 of Exercise 7A
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2
The base of a triangular field is three times its altitude. If the cost of sowing the field at Rs58 per hectare is Rs783, find its base and height.
It is given that the base of the triangular field is three times greater than its altitude
Let us assume height of the triangular field be x and base be 3x
We know that,
Area of triangle = 
× base × height
= 
× x × 3x
= 
x2
We know that,
1 hectare = 10,000 sq metre
Given,
Rate of sowing the field per hectare = Rs. 58
Total cost of sowing the triangular field = Rs. 783
Therefore,
Total cost = Area of the triangular field × Rs. 58
x = 300 m
Hence,
Height of the triangular field = x = 300 m
Base of triangular field = 3x = 3 × 300 = 900 m
