6. Secants, Tangents, and Angle Measures
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Recall the equation relating the angles between the lines and the measures of the intercepted arcs.
See solution.
Let's consider a circle, a tangent to the circle, and a secant such that they intersect outside the circle.
To find the value of x we will apply Theorem 10.14.
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Theorem 10.14 |
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If two secants, a secant and a tangent, or two tangents intersect in the exterior of a circle, then the measure of the angle formed is one half the difference of the measures of the intercepted arcs. |
In our case, we have that x is equal to half the difference between the measures of arcs QT and PT. m∠ A = x = 1/2(mQT - PT)