Answer:
90 degrees
Explanation:
The three angles of a triangle always add up to 180 degrees, so knowing this, all three of the measures given should add up to 180.
First, you need to solve for x:
S(x+10) + R(2x+60) + T(50+x) = 180
Add up all of the like terms:
10 + 60 + 50 = 120
x + 2x + x = 4x
So now you are left with 4x + 120 = 180
And solve for x:
4x/4 + 120/4 = 180/4
x + 30 = 45
x + 30-30 = 45-30
x = 15
Now that we have the value of x, plug it into the measure given for angle R:
(2x+60)
= (2(15)+60)
= (30 + 60)
= 90
So the measure of angle R is 90 degrees.
I hope this helped! :)