Let
ABCD be the given trapezium in which
AB=25m,
DC=13m,
BC=10m and
AD=10m.
Through C, draw CE∥AD, meeting AB at E.
Also, draw CF⊥AB.
Now, EB=(AB−AE)=(AB−DC)
=(25−13)m=12m;
CE=AD=10m; AE=DC=13m.
Now, in △EBC, we have CE=BC=10m.
So, it is an isosceles triangle.
Also, CF⊥AB
So, F is the midpoint of EB.
∴ EF=12×EB=6m.
Thus, in right-angled △CFE, we have CE=10m,EF=6m.
By Pythagoras theorem, we have
CF=√CE2−EF2
=8m.
Thus, the distance between the parallel sides is 8m.
Area of trapezium ABCD=12×(sum of parallel sides)×(distance between them)
=0.5×(25+13)×8m2
=152m2