Inside square ABCD, a point E is chosen so that triangle DEC is equilateral. Find the measure of ∠AEB.
Solution
Solution:
Since △DEC is an equilateral triangle, then ∣DE∣=∣CE∣ and each angle has a measure of 60∘. This implies that ∠ADE has measure of 30∘. Since ∣AD∣=∣DE∣, then △ADE is an isosceles triangle. Thus, ∠DAE=∠DEA=75∘. The same argument on triangle BEC will give us ∠CBE=∠CEB=75∘. Thus, ∠AEB=150∘.
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