Answer:
m∠TRI = 43
Explanation:
m∠TRI + m∠IRB = m∠TRB
3x - 5 + x + 27 = 86
3x + x - 5 + 27 = 86 {Combine like terms}
4x + 22 = 86 {Subtract 22 from both sides}
4x = 86 - 22
4x = 64 {Divide both sides by 4}
x = 64/4
x = 16
m∠TRI = 3x - 5
= 3*16 - 5
= 48 - 5
= 43