A geometry problem by Jimmy Gao

There are four squares A, B, C and D. A and C have triangles sides2cm and 1cm.
So area in A and C =2 {(1/2) 2 1}=2 cm^2.
Trangle in B has sides 1x1. area =(1/2)
1*1= 1/2 cm^2
D has a quarter circle radius 2cm. Area=(1/4) $\pi*2^2=\pi cm^2\\$
Total area = 2 + 1/2 + $\pi =5.64 cm^2$
Note all triangles are right angled and all sides taken are the legs.