The square base has side lengths of 10 millimeters. the height of one triangular face is 15 millimeters. find the total surface area of the square pyramid.

The formula for the surface area of a square pyramid is:
SA = (side times side) + #offaces(1/2 b times slantheight)
If you put all of the numbers into place it would be:
SA = (10 times 10) + 4(1/2 10 times 15)
Then:
SA = 100 + 4(1/2 150)
SA = 100 + 4(75)
SA = 100 + 300
SA = 400
So, the surface area of this square pyramid is 400mm squared.

You're welcome.

The correct answer is -20y