Suppose the number is x, its reciprocal is 1/x
x+1/x=13/6
(x^2+1)/x=13/6
6(x^2+1)=13x
6x^2-13x+6=0
(3x-2)(2x-3)=0
x=2/3 or x=3/2
Circumference of a circle is 2 x pi x r
18 - 7x = -20.5
Subtract 18 from each side:
-7x = -38.5
Divide both sides by -7:
x = -38.5 / -7
x = -5.5 = 5 1/2
The answer is D.
Answer: 32°
Step-by-step explanation: see photo