A small home speaker produces 0.200 ~\text{W}0.200 W of acoustical power. (This is achieved, for example, by a 10-Watt speaker operating at 2% electrical efficiency). If the speaker projects sound uniformly in all directions, what is the loudness of the sound (in dB) at a distance of 0.668 ~\text{m}0.668 m from the speaker?

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