Known :
r = 18 m
θ = 90° (because right angle)
Asked :
arc length = ...?
Answer :
Arc length
[tex] = \frac{θ}{360} \times 2\pi r \\ = \frac{90}{360} \times 2 \times \pi \times 18 \\ = \frac{1}{4} \times 36\pi \\ = 9\pi\: cm[/tex]
So, length of the red arc is 9π cm
Hope it helps and is useful :)
