In triangle CDE, angle C = 30 degrees, angle D = 45, CE = 5√2 cm. Find angle E, side DE.
| June 16, 2021 | education
The sum of the inner angles of the triangle is 180, then the angle CED = (180 – CDE – DCE) = (180 – 45 – 30) = 105.
By the sine theorem, we define the length of the side DE.
DE / Sin30 = CE / Sin45.
DE = CE * Sin30 / Sin45 = 5 * √2 * (1/2) / (√2 / 2) = 5 cm.
Answer: The CED angle is 105, the DE side length is 5 cm.
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