Answer:
Step-by-step explanation:
This is an Isosceles triangle, two of the angles are equal
A triangle has how many degrees in it? 180°
A two angles that form a line also has 180°
Think of two right angles 90° + 90° = 180° (I wish i could draw on this)
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90°|90°_
angle SRT = angle STR = 20°
angle STR + angle STU = 180°
20° + angle STU = 180° subtract 20° from both sides
angle STU = 160°
angle STU = 4x subs in 160°
160° = 4x divideboth sides by 4
40° = x <---------------- FINAL ANSWER D
