Answer:
<u>Option 2. ⇒ x = 28</u>
Step-by-step explanation:
Given that:
ΔABC , AB ≅ AC , m∠A = 3x and m∠B = x+20
m∠B ≅ m∠C because AB ≅ AC
So, m∠C = x+20
And we should know that, the sum of the interior angle of the triangle = 180
So, m∠A + m∠B + m∠C = 180
So, (3x) + (x+20) + (x+20) = 180
Solve for x
∴ 5x + 40 = 180
5x = 180 - 40 = 140
x = 140/5 = 28
<u>So, the answer is option 2) 28</u>