Answer :
Explanation :
The sum of the interior angles of a triangle is equal to 180° .
thus,
since, angle A and angle B are formed on the base of two congruent sides ( AB & AC respectively ) ,thus they're also congruent, hence,
- m∠A + 2m∠B = 180°
- (x + 5)° + 2(3x)° = 180°
- x° + 5° + 6x° = 180°
- 7x° + 5° = 189°
- 7x° = 180° - 5°
- 7x° = 175°
- x = 175°/7°
- x = 25
plugging in the value of x in the expression for angle A,
- m∠A = (x - 5)°
- m∠A = (25 - 5)°
- m∠A = 20°
thus, the measure of angle A is 20° .
