Answer is 30 °
Step by step
The three angles will equal to 180 degrees.
So we have
x + 15
4x - 15
X (our unknown)
x + 15 + 4x - 15 + x = 180
6x = 180
Divide both sides by 6 to solve for x
6/6 x = 180/ 6
x = 30
Check your work by substituting 30 for x
Our equation was
x + 15 + 4x - 15 + x = 180
30 + 15 + (4)(30) - 15 + 30 = 180
30 + 15 + 120 -15 + 30 = 180
180 = 180
Problem solved
