The proof, with a missing reason, proves that the measure of Statement Reason

M
m2DAE-90 Definition of a right angle

m2AED-22
Triangle Sum Theorem

DE joins the midpoints of
AB and AC Given

DE is parallel to BC
2
ECB
m
Which of the following can be used to fill in the missing reason?
Triangle Inequality Theorem
Midsegment of a Triangle Theorem
Concurrency of Medians Theorem
Isosceles Triangle Theorem