Midsegment for ACE?

(last question I just want to make sure I get this right)

There are 15 plates and each plate is either 7 or 12 inches diameter. which systems of equations do you use to find the number of 7 inch plates, x and 12 inch plates, y

The acceleration of an object due to gravity is 32 feet per second squared.what is acceleration due to gravity in inches per second squared?

Askateboard ramp is in the shape of a right triangle what is the height of the ramp