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Angles and Circles. Add examples from these slides to your notes!!!. EXAMPLE. Solution: Arc RQ = 360 – 140 – 100 Arc RQ = 120 o M<QPR = (1/2) 120 M<QPR = 60 o. Congruent Angles From same intercepted arc. If arc AB = 100 0 , then <1 = 50 0 and <2 = 50 0 because they both
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Angles and Circles Add examples from these slides to your notes!!!
EXAMPLE Solution: Arc RQ = 360 – 140 – 100 Arc RQ = 120o M<QPR = (1/2) 120 M<QPR = 60o
Congruent Angles From same intercepted arc If arc AB = 1000 , then <1 = 500 and <2 = 500 because they both Intercept the SAME ARC.
Tangent and Chord Angles Note: The angle is partially in the circle and out of the circle. The arc is from the tangent point to the other end of the chord. EXAMPLE
Angles formed by tangents and secants The measure of an angle formed by: * the intersection of 2 tangents to a point outside a circle is ½ the difference of the measures of the intercepted arcs. *the intersection of 2 secants *the intersection of a tangent and a secant
Note: <1 and <2 are NOT central angles, so they don’t equal the arcs! EXAMPLE
1. (3x+70)-(2x+30) = 40 2 (3x+70)-(2x+30) = 80 x+40 = 80 x = 40 Then: if x = 40, 2(40)+30 = 1100 3(40)+70 = 1900 so, Y = 360 - 110 - 190 = 600 2. (125)-(x) = 35 2 125 - x = 70 x = 55 Then: if x = 550, Y = 360 - 100 - 55 - 125 = 800 3. x = 180 - 80 (linear pair = 180) x = 100o Then: (120)+(y) = 100 2 120 + y = 200 y = 80o