Suppose D is a point in the interior of ⦟ABC. If ⦟ABD ≅ ⦟CBD, m⦟ABD =8x+18, and m⦟CBD= 5x+72. What is x?

Answer 1

The definition of congruent angles means that their measures are equal. If ∠ABD ≅ ∠CBD, then m∠ABD = m∠CBD. So, the equation we set up is:

8x + 18 = 5x + 72

x = 18

Hope this was helpful.