First solve for the other angles. You know one angle is 15º. The one across from it is also 15º since it is a vertical angle to the known 15º angle. Both of those together gets 30º. The whole thing is 360º, so just subtract 30 from 360 and divide. 360 - 30 = 330 Do the same for the 15x angle. The one under/across to it is a vertical angle so is also 15xº. Now you are left with 30xº = 330. Just divide now. 330 / 30 = 11 x = 11 15x = 165
Checking your work: 15x = 165 15x = 165 15 15 Those are the angles. Add those numbers together and make sure it adds up to 360º. 165 + 165 + 15 + 15 = 360 So this is correct.
