What is the answer to this question?

Answer:
Step-by-step explanation:
a. area of rectangle=lxh
lxh
12x6
=72
b.area of triangle =1/2xbxh
1/2xbxh
1/2x3x6
=9
c.area of triangle =1/2xbxh
1/2xbxh
1/2x3x6
=9
d.a=l^2
=6x6
=36