10. A rock climber ascends 18 feet to the top of a rock ledge. The climber descends 84 feet and takes a break on a rock outcrop. Write and evaluate
an addition expression to show how much farther the rock climber must
descend to reach the original level.

What is the next step in the given proof? choose the most logical approach. a. statement: m 1 + m 2 + 2(m 3) = 180° reason: angle addition b. statement: m 1 + m 3 = m 2 + m 3 reason: transitive property of equality c. statement: m 1 = m 2 reason: subtraction property of equality d. statement: m 1 + m 2 = m 2 + m 3 reason: substitution property of equality e. statement: 2(m 1) = m 2 + m 3 reason: substitution property of equality