Final answer:
To find the measure of angle RST, subtract the sum of angle R and angle S from 180 degrees.
Step-by-step explanation:
To find the measure of angle RST, we need to use the angle sum property of a triangle. In a triangle, the sum of the three angles is always 180 degrees.
We are given two angles: angle R and angle S, which are 40 degrees and 30 degrees, respectively.
To find angle T, we subtract the sum of angle R and angle S from 180 degrees: 180 - (40 + 30) = 180 - 70 = 110 degrees.
Therefore, the measure of angle RST is 110 degrees (option d).