Question

what is the missing reason in step 3? statements reasons 1. $mangle trv = 60^{circ};mangle trs=(4x)^{circ}$ 1. given 2. $angle trs$ and $angle trv$ are a linear pair 2. definition of linear pair 3. $mangle trs + mangle trv=180$ 3.? 4. $60 + 4x=180$ 4. substitution property of equality 5. $4x = 120$ 5. subtraction property of equality 6. $x = 30$ 6. division property of equality substitution property of equality angle addition postulate subtraction property of equality addition property of equality

Explanation:

A linear - pair of angles is supplementary, which means the sum of the measures of the two angles in a linear pair is 180 degrees. This is based on the angle - addition postulate. In step 3, since ∠TRS and ∠TRV are a linear pair (from step 2), we use the angle - addition postulate to say that m∠TRS + m∠TRV=180.

Answer:

angle addition postulate