Question

Find the area of a trapezium ABCD with AB parallel to CD
AB = 10cm
BC = 10cm
BC = 13cm
CD = 25cm
AD = 10cm

Answer 1

Let AB=11 cm, CD=6 cm and AB is parellel to CD.

Let distance between foot of perpendicular h and A

is X.

So distance between B and foot of 2nd perpendicular from C=11–6-x=5-x.

There are 2 rt. angled triangles.

Applying Pythogorous theorem,

For one triangle,

h^2=3^2-x^2—————(1)

For 2nd triangle,

h^2=4^2-(5-x)^2————-(2)

From (1)&(2), x=1.8 cm and

required h=2.4 cm