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Secant Angles & Arcs. Introduction. A Secant is a straight line that crosses/intercepts another shape. A Secant angle is an angle made from two secant lines. Arcs and Secant Angles. The secant angle equals half the difference between the measure of the two arcs. m_A = ½(mBC – mDE). B.
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Secant Angles & Arcs Introduction
A Secant is a straight line that crosses/intercepts another shape. A Secant angle is an angle made from two secant lines.
Arcs and Secant Angles The secant angle equals half the difference between the measure of the two arcs m_A = ½(mBC – mDE) B D A E C Angle = ½ (Big arc – Small arc)
Arcs and Secant Angles The secant angle is half of Arc BC – Arc DE Secant Angle = ½ (100 – 20) A=___ 40° ½ (80) = 40° B 100° D 20° A E C
Given the Angle: Solve for missing arc (x) A= 30° Do the inverse: MULTIPLY BY 2 A = ½ (BC – DE) 30 = ½ (110 – x) BC= 110° 2(30) = (110 – x) 50° DE= ___ 60 = (110 – x) Find the difference: • 110 • 60 • 50 B 110° D x A 30° E C
Introduction to Arcs and Secants For the front, you are looking for the angle. For the back, you are finding the missing arc. Due in class today. Homework is up front.