The angle is formed by intersecting chords. (That's how it got its name.) The vertex will be a point in the interior of the circle. The angle will equal one half the sum of the intercepted arcs.

Geometry (Part 1) Lines and angles A line is an infinite number of points between two end points. Where two lines meet or cross, they form an angle. An angle is an amount of rotation. It is …

To find the value of a trigonometric function of an angle in the I, II, III, and IV quadrants by rotating clockwise, we will make use of the reference angle of the angle.

Students describe the angle relationship in the diagram and set up and solve an equation that models it. Have students verify their answers by measuring the unknown angle with a protractor.

Example: Rewrite each expression in terms of its reference angle, deciding on the appropriate sign.

The question “What is the subtended arc of this angle?” is asked to let students notice the subtended arc, AB, of ∠AOB. Then, let students use another protractor, called C, to construct …

Example: Find the measure of angle 1 if the measure of angle 2 is 56 degrees and Practice: If and , find the measure of angle 3. Justify each step.