Answer:
<C=48 because 90-42=42 as in the other side of the triangle.
<B=42 because vertical angles are always congruent.
<B+<D=90 because <D is 48 because it is vertical to <C
length: 10
width: 3
height: 1
10 x 3 x 1=30
what I have to find ............???????
