Find the value of a and b

Since this triangle is an isosceles triangle , it's opposite base angles will be equal . Which means :-

∠a = ∠b ( opposite base angles )

Angle sum property :- Sum of all angles in the interior of a triangle will be equal to 180° .

Which means :-

80° + ∠a + ∠b = 180°

Let us name both the angles as 'n' as their values are equal . Then :-

80° + n + n = 180°

80° + 2n = 180°

2n = 180 - 80

2n = 100

n = 100 ÷ 2

n = 50

Which means :-

Value of ∠x :-

as x is the exterior angle it will be equal to the sum of its interior opposite angles .

∠x = 80° + 50°

∠x = 130°

Therefore , the value of ∠a = 50° and ∠b = 50° .

for the points! : )

abde or 1,2,4, 5 is the answer

step-by-step explanation: