Your answer is C.
Round all the numbers then multiply since it says estimate.
Π = 3.14 = 3
3.75 = 4
6.21 = 6
3•4^²•6 = 288
The 3 inside angles of a triangle equal 180.
Add the 3 angles together to equal 180:
X + (5x-20) + 4x = 180
Simplify the left side by adding like terms:
10x-20 = 180
Add 20 to each side:
10x = 200
Divide both sides by 10:
x = 20
Angle A = x = 20
Angle B = 4X = 4(20) = 80
Angle C = 5x-20 = 5(20) -20 = 100-20 = 80

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Write an out an equation using the information given. So:
8 + 5 + x - 2 = 14.5
<span>13 + x - 2 = 14.5 </span>
<span>11 + x = 14.5 </span>
<span>x = 3.50
This means that the answer is D.
Hope this helped :)</span>