Find the GCD (or HCF) of numerator and denominator
GCD of 18 and 20 is 2
Divide both the numerator and denominator by the GCD
18 ÷ 2
-----------
20 ÷ 2
Reduced fraction:
9
----
10
Angle 2 = 22 degrees (that line is dividing that angle into 1 & 2 equivalently)
Angle 3 = 90 degrees.
Your answer is 18 :)
work:
pi(2)d
pi(72)
72/2=36=d
2r=d
36/2=18=r
This answer would be (55/9, ∞)