Area (Polygon, Triangle, Circle, Square) Examples

Which of the following is the formula for the area of a triangle? a) base × height b) πr² c) ½ (base 1 + base 2) × height d) ½ (base × height)
A triangle is half of a rectangle.
The area of a triangle is half the area of a rectangle.
The area of a rectangle is base × height, so the area of a triangle is 1/2 (base × height)

Which numbers would be multiplied to find the area of the parallelogram below?
The formula for the area of a parallelogram is base × height. The base, or bottom of the parallelogram, is 12 inches.
The height is the distance from base to base, or the length of the perpendicular line between the two bases. The height of this parallelogram is 8 inches.
So 12 in and 8 in would be multiplied to find the area of the parallelogram.

The area of the circle is πr². Which number would be squared to find the area of the circle below?