Question

the length and breadth of rectangular field are in the ratio 5:4.If the area of field is 980 m².Find the cost of fencing at Rs 20 per metre

Answer 1

Let the length and breadth be 5x and 4x
area of field = 980
length × breadth = 980
5x × 4x = 980
20x^2 = 980
x^2 = 980/20 = 49
x = 7m
length = 5x = 5×7 = 35m
breadth = 4x = 4×7 = 28m
that is for finding length and breadth
Now
perimeter of field = 2 (l+b) = 2 (35+28) = 2×63 = 126m
cost of fencing field = 126 × 20 = Rs 2520