Question

Will mark brainliest, help me answer this question!

Answer 1

Answer:

135 degrees

Step-by-step explanation:

• Angle CBD is the sum of angle ABC and angle ABD, so we find these first
• An Isosceles triangle has 2 equal sides and 2 equal angles
• Isosceles triangle theorem tells us that the 2 equal angles are respectively opposite the equal sides
• Since triangle ABC has sides AB=AC, then angle ACB = angle ABC
• So knowing that angles of triangle add up to 180, then
• $\angle CAB+\angle ACB+\angle ABC=180\\(50)+\angle ACB+\angle ABC=180\\50-(50)+\angle ACB+\angle ABC=180-(50)\\\angle ACB+\angle ABC=130\\But,\angle ACB=\angle ABC,so\\(\angle ABC)+\angle ABC=130\\2\angle ABC=130\\\angle ABC=65$
• Now we do the next triangle to get ABD
• Since triangle ABD has sides AB=BD, then angle BDA = angle BAD
• So knowing that angles of triangle add up to 180, then
• $\angle BDA+\angle BAD+\angle ABD=180\\(55)+\angle BAD+\angle ABD=180\\But,\angle BDA=\angle BAD,so\\(55)+(55)+\angle ABD=180\\110+\angle ABD=180\\110-(110)+\angle ABD=180-(110)\\\angle ABD=70$
• Now we said, angle CBD is the sum of angle ABC and angle ABD, so
• $\angle ABC+\angle ABD=\angle CBD\\(65)+(70)=\angle CBD\\\angle CBD=135$

Answer 2

Answer:

135. isosceles triangles have two equal sides/angles. <CBD is 135, from adding 70 and 65.