Question

GEOMETRY!!!!!!

Triangles ACD and BCD are isosceles. Angle BAC has a measure of 18 degrees and angle BDC has a measure of 48 degrees. Find the measure of Angle ABD.

What is the measure of angle ABD?
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Answer 1

138°

Explanation:

∠BCD and ∠CDB are equivalent, meaning they both are 48°. Together, that is 96°. Subtract 96° from 180° (the measure of all of the inside angles in a triangle added together.) and you get 84°. Subtract 84° from 360° (the number of degrees in a circle) and you get 276°. Divide that by two (∠ABD and ∠ABC) to get 138°.