Final answer:
To find the measure of angle ZB (mZB), subtract the measure of angle ZA (mZA) from 180°. Since mZA is 159°, mZB is 180° - 159°, which equals 21°.
Step-by-step explanation:
If the measures of angles ZA and ZB are supplementary, it means that the sum of mZA and mZB is 180 degrees. Given that mZA = 159°, we can find mZB by subtracting the measure of ZA from 180 degrees.
To find mZB, we use the equation:
mZA + mZB = 180°. Substituting the known measure in, we get 159° + mZB = 180°. To solve for mZB, subtract 159 degrees from both sides of the equation.
mZB = 180° - 159°, which equals 21°.
Therefore, mZB is 21°.
To find mZB, we need to use the fact that supplementary angles add up to 180 degrees. Given that mZA = 159 degrees and ZA and ZB are supplementary, we can use the equation mZA + mZB = 180 to solve for mZB. Substituting in the given value, we have 159 + mZB = 180. Solving for mZB, we have mZB = 180 - 159. Therefore, mZB = 21 degrees.