Two radioactive samples decay at different rates as shown on the graph. Which is closest to the time that these two samples are equal in mass?

A. 0.9 years
B. 1.8 years
C. 2.3 years
D. 3.0 years

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