Find the remaining interior angle in the triangle.

Since we know that all the interior angles add up to 180° according to the Angle Sum Theorem, we can write an equation and then fill in what we know.

m∠1 + m∠2 + m∠3 = 18052 + 63 + m∠3 = 180m∠3 = 65

That means our remaining interior angle is 65°.