09. MENSURATION
290092
A rectangular field has its length and breadth in the ratio 5 : 3 Its area is 3.75 hectares the cost of fending it at Rs 5 per metre is:
1 Rs 400
2 Rs 4000
3 Rs 1000
4 Rs 500
Explanation:
Rs 4000
Let the length and breadth be 5x and 3xArea = 3.75 hectares = 3.75 × 10000 = 37500.00sq.meter
\(\therefore\) 3x \(\times\) 5x = 37500 \(\Rightarrow\) 15x\(^{1}\)= 37500
\(\Rightarrow\)15x\(^{1}\)= 37500
\(\Rightarrow\) x\(^{1}\)= 2500
x\(^{1}\)= 2500
\(\Rightarrow\) x = 50
\(\therefore\) length = 5 × 50 = 250m Breadth = 3 × 50 = 150m Perimeter of the field = 2(l + b) = 2(250 + 150) ? 2(250 + 150) ? 2 × 400 = 800m
\(\therefore\) Cost of fancing=800 × 5 = Rs. 4000
