∠a:
m∠a + 50 = 180 (because they are supplementary angles)
m∠a + 50 (-50) = 180 (-50)
m∠a = 180 - 50
m∠a = 130°
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m∠d + 65 + 50 = 180
m∠d + 115 = 180
m∠d + 115 (-115) = 180 (-115)
m∠d = 65°
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hope this helps
