High School · Circles

CCSS.MATH.CONTENT.HSG.C.B.5

Derive using similarity the fact that the length of the arc intercepted by an angle is proportional to the radius, and define the radian measure of the angle as the constant of proportionality; derive the formula for the area of a sector.

Read this standard on the official Common Core site

Lessons that teach this standard

• Arc Length, Sector Area and Radian Measure

  Why all circles are similar, why an arc's length is proportional to its radius, how that ratio defines the radian, and the formulas for arc length and sector area.