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The perimeter of a movie screen is 54 meters. the screen is 18 meters wide. how tall is it?

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b