Question

find the value of the unknown exterior angle ACD in the following figure
a. angle A = Angle B - 25° ​

Answer 1

Answer:

In triangle ACD

angle ACB = 130°

and AD is a straight line , so it will make an angle of 180°

So, we can say

angle ACB + angle ACD = 180°

130 + angle ACD = 180

angle ACD = 180 - 130

angle ACD = 50 °

ANOTHER METHOD

We know that in a Triangle an exterior angle is equal to sum of 2 opposite angles

so, angle BAC + angle ABC = angle ACD

25° + 25 ° = angle ACD

25° + 25 ° = 50°