Lesson Plan

Find unknown angles, arc measures, and lengths in a circle figure by combining the relationships below with triangle facts (two radii make an isosceles triangle; a right angle allows the Pythagorean theorem)

State an arc's measure in degrees from its central angle, distinguish it from the arc's length, and use that a central angle equals the measure of its intercepted arc

Apply the inscribed angle theorem: an inscribed angle equals half the measure of its intercepted arc

Use the corollary that inscribed angles subtending the same arc are congruent

Recognize and apply the theorem that an inscribed angle in a semicircle (subtending a diameter) is 90°

"Use definitions, properties, and theorems relating to circles and parts of circles such as radii, diameters, tangents, angles, arc lengths, and sector areas to solve problems."