∠A and ∠B are vertical angles. If m∠A=(4x+8)∘ and m∠B=(5x−3)∘, then find the measure of ∠A.
Vertical angles are congruent, so m∠A = m∠B.
4x+8 = 5x-3
Subtract 5x from both sides.
Subtract 8 from both sides to isolate the variable.
Divide both sides by -1 to solve for x.
Plug in 11 for x into m∠A=(4x+8)=(4(11)+8)=(44+8)=52.