160 likes | 520 Views
9.4 ~ Angles formed by Secants & Tangents. Three cases to consider. How many different ways can you think of involving the intersection of two lines and a circle? The lines can be secants or tangents or one of each. (CASE 1). Vertex is ON the circle. 2 Secants. Secant & Tangent.
E N D
Three cases to consider • How many different ways can you think of involving the intersection of two lines and a circle? • The lines can be secants or tangents or one of each.
(CASE 1) • Vertex is ON the circle 2 Secants Secant & Tangent
(CASE 2) • Vertex is IN the circle 2 Secants
(CASE 3) • Vertex is OUT of the circle 2 Secants Secant & Tangent 2 Tangents
Formulas • ON – Vertex is ON the circle • Angle = ½ Arc • IN – Vertex is IN the circle (not center) • Angle = ½ (Arc + Arc) • OUT – Vertex is OUT of the circle • Angle = ½ (Arc – Arc)