Angles Formed by Tangents to a Circle

Math II 7.4 RSG 11 Based on Lesson 7.4 from Open Up Resources openupresources.org Examine the relationships between circumscribed angles and circles. We have seen that circles can be inscribed in triangles so that the circle is tangent to all three sides. What relationship exists between the radii of the inscribed circle and the sides of the triangle that are tangent to the circle? How do I construct lines that are tangent to a circle from a point that lies outside the circle? How do I measure a circumscribed angle formed by two intersecting lines tangent to a circle?