Suppose ABC is a triangle in the plane as pictured below:
A
C
d. Deduce that m(LA) + m(zB) + m(C) = 180
B
Suppose M is the midpoint of AC and N is the midpoint of BC.
a. Draw the rotation of AABC by 180 degrees about M, labeling the image of B as B'.
b. Draw the rotation of AABC by 180 degrees about N, labeling the image of A as A'.
c. Explain why B', C', A' and are collinear.