See The Parallel Sides Are 40cm And 16cm
So Longer Side Differs From the shorter side by 40-16= 24 cm
Or 24/2 = 12 cm
Hence On Each Side THE LONGER SIDE HAS 12 cm Extra
It Will Act As Base
Hypoteneuse = Non Parallel Sides
Height ^2= 13^2-12^2
Height ^2 = 25
Height = 5cm
Now Area = 1/2*(42+16)*5= 145cm^2