Question

Find the length of YXZ. A.s=3 B.s=60 C.s=75 D.s=236

Answer 1

R = 15

The circumference of circle: $C=2\pi r$

subtitute: $C=2\pi\cdot15=30\pi$

$1\ rad=\dfrac{180^o}{\pi}\to5\ rad=5\cdot\dfrac{180^o}{\pi}=\dfrac{900^o}{\pi}$

$\dfrac{5\ rad}{360^o}=\dfrac{\frac{900^o}{\pi}}{360^o}=\dfrac{900^o}{\pi}\cdot\dfrac{1}{360^o}=\dfrac{5}{2\pi}$

$s=\dfrac{5}{2\pi}C\to s=\dfrac{5}{2\pi}\cdot30\pi=75$

Answer: C. s = 75