The answer is:
The reason is:
bottom one is a square prism. the volume formula is l x w x h. 9 x 9 x 9
square prism : 729
then the top one is a triangular prism. which is 1/2b x a x a
so 3.5 x 9 x 9
triangular prism: 283.5
then add these 2 numbers
1012.5