Answer: A. 50
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Step-by-step explanation:
The order of the lettering is important when it comes to similar polygons. This is because the order tells us how the letters pair up.
I don't recommend using solely the diagram to try to see how the angles pair up because the diagram might not be to scale. So we'll just be focused on the lettering.
In the sequences ABCDE and PQRST, we have letters E and T as the last items. This means they correspond and pair up together. Furthermore, these angles are congruent (since similar polygons have congruent corresponding angles).
So in short, E = T.
The diagram shows E = 110 and T = 2x+10
This leads to...
E = T
110 = 2x+10
2x+10 = 110
2x = 110-10
2x = 100
x = 100/2
x = 50