vertical angles

Question

Angle 3 and Angle 5 are vertical angles. The measure of Angle 3 is (12x - 5). The measure of Angle 5 is (10x + 15). What is the measure of each angle?

Answer 1

Remember that vertical angles are equal to 180 degrees. You solve each equation like a one step equation. You have equal each equation to 90 degrees. Then you solve to for x.

Answer 2

Vertical angles are congruent, so they have equal measures. So set them equal to one another and solve for x. Plug the value of x you get back into the equation for each angle to get the measures. If you did it right, they'll have the same measure. Don't forget the units - degrees!