Understanding Inscribed Angles and Arc Relationships in Circles
Dive into the concepts of central angles, inscribed angles, and their relationships within circles. Learn that the measure of an inscribed angle is half that of its intercepted arc. Explore examples that illustrate how to calculate unknown angles using given measurements and the properties of inscribed and central angles. Understand how inscribed polygons relate to circumscribed circles, including properties of supplementary angles in quadrilaterals and triangles. This guide offers clarity on geometric relationships essential for mastering circle theorems.
Understanding Inscribed Angles and Arc Relationships in Circles
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Presentation Transcript
Warm up 30 80 100 180 100 260
Central Angle Angle = Arc
Inscribed Angle • Angle where the vertex is ON the circle
160 The arc is twice as big as the angle!! 80
Find the value of x and y. 120 120 x 60 y
J K Q S M Examples 1. If mJK= 80 and JMK = 2x – 4, find x. x = 22 2. If mMKS= 56, find m MS. 112
Find the measure of DOG and DIG D 72˚ G If two inscribed angles intercept the same arc, then they are congruent. O I
If all the vertices of a polygon touch the edge of the circle, the polygon is INSCRIBED and the circle is CIRCUMSCRIBED.
Quadrilateral inscribed in a circle: opposite angles are SUPPLEMENTARY B A D C
If a right triangle is inscribed in a circle then the hypotenuse is the diameter of the circle. diameter
Q D 3 J T 4 U Example 3 In J, m3 = 5x and m 4 = 2x + 9. Find the value of x. x = 3
Example 4 In K, GH is a diameter and mGNH = 4x – 14. Find the value of x. 4x – 14 = 90 H K x = 26 N G
Example 5 Find y and z. z 110 110 + y =180 y y = 70 85 z + 85 = 180 z = 95