University:
High School
Course:
High School Geometry
Academic year:

2020
Views:

496

Pages:

6
Author:

Nelson Avila

10.1 Notetaking with Vocabulary (continued) Extra Practice In Exercises 1-6, use the diagram. Name two radii. AB, AF or AD Name a chord. CE Name a diameter. DF Name a secant. DE Name a tangent. Line B Name a point of tangency. Point B In Exercises 7 and 8, use the diagram. Tell how many common tangents the circles have and draw them. Tell whether each common tangent identified in Exercise 7 is internal or external. In Exercises 9 and 10, point D is a point of tangency. Find BD. (5.5)² + (BD)² = 10² 30.25 + (BD)² = 100 (BD)² = 69.75 BD = 8.41 Point C is also a point of tangency. If BC = 4x + 6 in, find the value of x to the nearest tenth. 10.1 Notetaking with Vocabulary (continued) Core Concepts Lines and Segments That Intersect Circles A segment whose endpoints are the center and any point on a circle is a radius. A chord is a segment whose endpoints are on a circle. A diameter is a chord that contains the center of the circle. A secant is a line that intersects a circle in two points. A tangent is a line in the plane of a circle that intersects the circle in exactly one point, the point of tangency. The tangent ray AB and the tangent segment AB are also called tangents. Coplanar Circles and Common Tangents In a plane, two circles can intersect in two points, one point, or no points. Coplanar circles that intersect in one point are called tangent circles. Coplanar circles that have a common center are called concentric circles. 2 points of intersection 1 point of intersection (tangent circles) no points of intersection (concentric circles) A line or segment that is tangent to two coplanar circles is called a common tangent. A common internal tangent intersects the segment that joins the centers of the two circles. A common external tangent does not intersect the segment that joins the centers of the two circles. 10.2 Notetaking with Vocabulary (continued) Extra Practice In Exercises 1-8, Identify the given arc as a major arc, minor arc, or semicircle. Then find the measure of the arc. AB = 70° Minor ABC = 180° Semicircle ABD 120° + 90° = 210° Major BC = 90° Minor BAC = 140° 90° + 40° = 130° Minor DAB = 190° 140° + 90° = 230° Major AD = 140° Minor CD = 40° Minor In ⊙E above, tell whether ABC ≅ ADC. Explain why or why not. Yes, Both are semicircles that equal 180°. In ⊙K, find the measure of DE. 125° Find the value of X. Then find the measure of AB. 5x + 40 + 70 + 75 + 2x = 360° 7x + 185 = 360 7x = 175 x = 25 AB = 5(25) = 125°