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# triangle geometry

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In the diagram below, BC = EC and ECD = 138.  Find ABE.

Mar 19, 2021

#1
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if BC = EC, then angle CEB and EBC must be equal as well.

the exterior angle of a triangle is always the some of the other two angles in that triangle.

following this, we can also conclude that angle EBC is simply 138 / 2 = 69.

now we can solve angle ABE, which is just 180 - 69 = 111, because those two angles are on the same straight angle.

hope this helped! sorry if my explanations weren't too clear. please let me know if you are confused about anything i did

Mar 19, 2021

#1
+141
+1

if BC = EC, then angle CEB and EBC must be equal as well.

the exterior angle of a triangle is always the some of the other two angles in that triangle.

following this, we can also conclude that angle EBC is simply 138 / 2 = 69.

now we can solve angle ABE, which is just 180 - 69 = 111, because those two angles are on the same straight angle.

hope this helped! sorry if my explanations weren't too clear. please let me know if you are confused about anything i did

idyllic Mar 19, 2021