Answer:
Part A: D.

Part B: Smaller angle
, larger angle
Step-by-step explanation:
The term supplementary is used when the sum of two angles add to
.
Part A:
From the information given that the "angles are supplementary" and the "measure of one angle is 3 times the measure of the other", the equation to find for x can be written as:

Part B:
To find the measure of each angle, we can first find the measure of the smaller angle
:



The smaller angle is

Since the measure of the larger angle is
times the measure of the smaller angle:
Larger angle



The measure of the larger angle is

Hope this helps :)