Will mark brainliest, help me answer this question!

135 degrees

Step-by-step explanation:

Angle CBD is the sum of angle ABC and angle ABD, so we find these firstAn Isosceles triangle has 2 equal sides and 2 equal anglesIsosceles triangle theorem tells us that the 2 equal angles are respectively opposite the equal sidesSince triangle ABC has sides AB=AC, then angle ACB = angle ABC So knowing that angles of triangle add up to 180, thenNow we do the next triangle to get ABDSince triangle ABD has sides AB=BD, then angle BDA = angle BAD So knowing that angles of triangle add up to 180, thenNow we said, angle CBD is the sum of angle ABC and angle ABD, so

The first answer is correct