Example 2
Five steps of a proof are shown. Write the reasons for each statement.
Given A4BC
Prove m/1+mZ2+ m23 = 180°
STATEMENTS
1. AABC
2. Draw BD parallel to AC.
3. m/4+m2+ m25= 180°
4. 41= 24, 23 = 25
5. m1=m24, m/3=m25
6. m/1+m2+ m/3 = 180°
Corollary to a Theorem
REASONS
1. Given
2. If there is a line and a point not on the line, then
there is exactly one line through the point parallel
to the given line.
3.
4.
5.
6.