Given:
m∠T = 61°
m∠S = 5x - 15
m ext∠TUV = 8x - 8
To find:
The measure of exterior angle TUV
Solution:
STU is a triangle.
By exterior angle of triangle property:
The measure of an exterior angle is equal to the sum of the opposite interior angles.
m ext∠TUV = m∠T + m∠S
8x - 8 = 61 + 5x - 15
8x - 8 = 46 + 5x
Add 8 on both sides.
8x - 8 + 8 = 46 + 5x + 8
8x = 54 + 5x
Subtract 5x from both sides.
8x - 5x = 54 + 5x - 5x
3x = 54
Divide by 3 on both sides.
x = 18
Substitute x = 18 in m ext∠TUV.
m ext∠TUV = 8(18) - 8
= 144 - 8
= 136
Therefore measure of exterior angle ∠TUV is 136°.