Question

The parallel edges of trapezium shaped field are 77m and 60m.if the remaining edges are 25m and 26m ,what is the total cost of digging twice the land at the rate of Rs 10 per square meter and fencing the land three times at the rate of Rs 20 per meter?

Answer 1

Answer:

From each of the ends of the 60 m side, draw altitudes to the 77 m side.

You now have a rectangle and two right-angled triangles.

Let the height of all three be h,

for the triangle with hypotenuse 25, let the base be x, then

x^2 + h^2 = 25^2 -----> h^2 = 625 - x^2

for the triangle with hypotenuse 26, let the base be 10-x

h^2 + (10-x)^2 = 26^2 ---> h^2 = 376 - (10-x)^2

625 - x^2 = 376 - (10-x)^2

a bit of simple algebra yields:

x = 49/20 = 2.45 m

now you can find the base of the other triangle , 10-x

and the height h

All is now known, and you can find area, perimeter or whatever else you need.