Question 11: Please help, Which statement(s) should be used in proving that vertical angles 1 and 3 are congruent?

Answer:
B. m < 1 + m < 2 = 180; m < 2 + m < 3 = 180.
Step-by-step explanation:
m < 1 + m < 2 = 180 so m < 1 = 180 - m < 2
m < 2 + m < 3 = 180 so m < 3 = 180 - m^2.
So by the transitive property of equality m < 1 = m < 3.