Answer:
∠ R = 76°
Explanation:
Since RS = RT , then Δ RST is isosceles with base angle being congruent (equal), so
∠ S = ∠ T = 2x + 2
The sum of the 3 angles in the triangle is 180°
sum the angles, equate to 180 and solve for x
3x + 1 + 2x + 2 + 2x + 2 = 180 ( collect like terms on left side )
7x + 5 = 180 ( subtract 5 from both sides )
7x = 175 ( divide both sides by 7 )
x = 25
Then
∠ R = 3x + 1 = 3(25) + 1 = 75 + 1 = 76°