Angle STR = 28 (since this angle is equal to SRT = 28) Angle STU = 2x
The two angles STR and STU form a straight angle. They are supplementary. This means they add to 180 degrees (angle STR) + (angle STU) = 180 28 + 2x = 180 .... substitution property 2x + 28 = 180 2x + 28 - 28 = 180 - 28 ... subtract 28 from both sides 2x = 152 2x/2 = 152/2 ... divide both sides by 2 x = 76
