Using Trig to Find Angles Mar 12, 3:25:58 PM
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In ΔCDE, the measure of ∠E=90°, DE = 84 feet, and EC = 13 feet. Find the measure of ∠C to the nearest tenth of a degree.
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If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.