Question

Find the measure of angle BDE. ML ABC=155

and muc=60.
155
C
B
bo
x
E

Answer 1

∠ BDE = 85°

Explanation:

The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.

∠ ABC is an exterior angle of the triangle, then

∠ C + ∠ BDC = 155

60 + ∠ BDC = 155 ( subtract 60 from both sides )

∠ BDC = 95°

∠ BDE and ∠ BDC are adjacent angles and are supplementary, thus

∠ BDE = 180° - 95° = 85°