Question 87623
Let the angles be A, B, and C.
From the problem description, you can write:
A = 3B  "One angle is 3 times a second."
C = B+20  "The third angle is 20 degrees more than the second angle."
So, we are looking for the measure of angle B, the second angle.
You already are aware that, in any triangle, the sum of the angles is 180 degrees, so you can write:
A + B + C = 180  Now substitute for A and C their equivalent values from above:
(3B) + B + (B+20) = 180  Simplify and solve for B.
5B + 20 = 180  Subtract 20 from both sides.
5B = 160  Divide both sides by 5.
B = 32 degrees.

Check:
A+B+C = 180
3(32)+32+(32+20) = 180
96+32+52 = 180
180 = 180 Check!