QR Math question

Question

A pancake 4 inches in diameter contains 7 g of fat. How many grams of fat are in a pancake 6 inches in diameter?

Answer 1

Assuming the same thickness of the pancake, we compare volumes of the pancakes, let the thickness be

1 unit.

Volume Pancake 1 = (pi*D²/4)(1) = pi*(4)²/4 = 4*pi in³

Volume Pancake 2 = (pi*(6)²/4) = 9*pi in³

Pancake 2 is 9*pi/4*pi = 9/4 "larger" and would have 9/4 times the fat in pancake 1

So, the fat in Pancake 2 = (9/4)*7 = 15.75 grams of fat