Question

1
Select the correct answer from each drop-down menu.
E
Points A, B, and form a triangle. Complete the statements to prove that the sum of the interior angles of ABC is 180°.
Statement
Reason
Points A, B, and C form a triangle.
given
Let DE be a line passing through Band parallel to AC. definition of parallel lines
23 25 and 21 - 24
m21 = m 24 and mZ3 = m 25
m24+ m2 2 + m 25 = 180°
angle addition and definition of a straight line
substitution
m21 + m22+ m23 = 180°

Answer 1

SOLUTION

Statement

$\angle3\cong\angle5\text{ and }\angle1\cong\angle4$

Reason

Alternate interior angles

Statement

$m\angle1=\angle4\text{ and }\angle3=\angle5$

Reason

Alternate interior angles are congruent