C) 304
Explanation below:
First, we can easily find the area of the base, since it's a square, 8 × 8 = 64.
Now, let's keep that in find and find the area of the 4 congruent triangles. Triangle's area is base × height / 2, so in this case 8 × 15 / 2 = 60. Multiply this by 4 for all 4 triangles and we have 240.
240 + 64 = 304.
Hope that helps!
:D®
