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Warm up (TI). Determine whether the arc is a minor arc, major arc or semicircle. PLM NL. mLN mPLN x. L. M. 40 °. 142 °. 38 °. N. K. 5x °. P. Inscribed Angles. Chapter 10 section 3. What is an inscribed angle?.
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Warm up (TI) • Determine whether the arc is a minor arc, major arc or semicircle. • PLM • NL • mLN • mPLN • x L M 40° 142° 38° N K 5x° P
Inscribed Angles Chapter 10 section 3
What is an inscribed angle? • An inscribed angle is an angle whose vertex is on a circle and whose sides contain chords of the circle. Intercepted arc
Theorem • An inscribed angle is ½ the measure of its intercepted arc. B m<BOM = 1/2mBM O M
Examples • Find the following measures. P S m PSR= Q R
Example W m ZWX = Z X 115° Y
Example N 100° M m< NMP = P
Find the m<ACB, m<ADB and m<AEB A 60° B E C D
Theorem • If two inscribed angles of a circle intercept the same arc, then they are congruent!
Inscribed/Circumscribed • A polygon is inscribed in a circle if all the vertices of the polygon lie on the circle. • The circle above is circumscribed about the polygon.
Theorem • If a right triangle is inscribed in a circle, then the hypotenuse is a diameter of the circle. The converse is also true.
Theorem • A quadrilateral can be inscribed in a circle iff the opposite angles are supplementary. O M V E
3x Example • Find the value of each variable. y x 85 80
Example…you’ll love this! • Find the measure of each angle. B 19y 10y A C 40x 22x D