Hi there! :)
Answer:
The answer is D. 83°
Explanation:
You should know that the interior angles of a triangle always add up to 180°.
So, what you will need to do, is add all 3 angles together and create an equation (equal to 180). Then you need to solve this equation by isolating "x":
(8x + 12) + (55 - 3x) + (10x + 23) = 180
Get rid of all the parentheses
8x + 12 + 55 - 3x + 10x + 23 = 180
Add all similar terms together
8x - 3x + 10x = 15x
12 + 55 + 23 = 90
15x + 90 = 180
Subtract "90" from each side of the equation → 180 - 90 = 90
15x = 90
Divide each side of the equation by "15" → 90 ÷ 15 = 6
x = 6
Since you now know that the value of "x" is 6, you can now find the measure of the angle at George's position by replacing the "x" by 6:
10x + 23 = Measure of the angle at George's position
10(6) + 23
Multiply 10 by 6 → 10 × 6 = 60
60 + 23
Add 60 and 23 together → 60 + 23 = 83
83 = Measure of the angle at George's position
There you go! I really hope this helped, if there's anything just let me know! :)