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Teachers & SchoolsStudy Guide

Let's go over these area formulas one more time.

**Area of a Rectangle** = Base × Height

**Area of a Square** = Base × Height

**Area of a Square** = *s*^{2}

A square, technically speaking, is a rectangle (don't remind the rectangle, it's a little sensitive), so we can use the formula for the area of a rectangle to find the area of a square. Since a square's base and height are equal, the area of a square is also side length times side length, or side length squared. We're way too lazy to write out "side length" so we're going to abbreviate it as *s*, which makes Area = *s*^{2}.

**Area of Triangle** = ½(Base × Height)

The height of a triangle is the length of a line that connects the base and vertex and is perpendicular to the base. So, the height has to square up with the base.

**Area of Parallelogram** = Base × Height

The height of a parallelogram goes from one base to the other and has to meet both bases at right angles.

**Area of Trapezoid** = ½(Base_{1} + Base_{2}) × Height

The height of a trapezoid, like the height of a parallelogram, is the distance between the two bases

**Area of Circle** = π(radius)^{2 }= π*r*^{2}

Pi, or π, is the ratio of the circumference to the diameter and is an irrational number. What we need to remember for the formula, though, is that π is often rounded to 3.14.