Data:
l and m are parallel lines
QR and ST are perpendicular in R
Angle 1 is 63°
The angle formed by perpendicular lines is a right angle (90°)
Angles 1 and 3 are alternate angles: angles that occur on opposite sides of a transversal line that is crossing two parallel.
Alternate angles are congruent, have the same measure.
The sum of the interior angles of a triangle is always 180°. In triangle QRT:
Use the equation above to find the measure of angle 2:
