In a square, multiply the In a rectangle, multiply side times the side. the base times the height. A=sxs A=bxh The area of some In a right triangle, one leg basic geometric is the base and shapes the other is the height. Multiply In a triangle, multiply half the base half the base times the times the height. height. A = ½ b x h A=½bxh A=½bxh In a circle, multiply pi times the radius squared. A= r2.