New York City SHSAT 2017

CIRCLES

93. Circumference of a Circle

Circumference = 2 πr

In the circle above, the radius has a length of 3, so the circumference is 2 π(3) = 6π.

94. Length of an Arc
    An arc is a piece of the circumference. If n is the degree measure of the arc’s central angle, then the formula is this: