The measure of ∠RST(angle S) can be found using the external angle theorem and the measure of ∠RST is 49 degrees.
It states that the measure of an exterior angle is equal to the sum of the measures of the two opposite(remote) interior angles of the triangle
Therefore,
∠SRT + ∠RST = 128°
let
∠RST = x
Therefore,
79 + x = 128
subtract 79 from both sides of the equation
79 - 79 + x = 128 - 79
x = 49°
Therefore,
∠RST = 49°
learn more on triangles here: https://brainly.com/question/9524036?referrer=searchResults
