Answer:
Option A. 4 radians
Step-by-step explanation:
step 1
Find the circumference of the circle
The circumference is equal to
[tex]C=2\pi r[/tex]
we have
[tex]r=5\ cm[/tex]
substitute
[tex]C=2\pi (5)[/tex]
[tex]C=10\pi\ cm[/tex]
step 2
Find the measure of angle [tex]\theta[/tex]
we know that
The circumference of the circle subtends a central angle of 2π radians
so
using proportion
Find out the central angle by an arc length of 20 cm
[tex]\frac{10\pi}{2\pi}=\frac{20}{x}\\\\x=2\pi (20)/10\pi\\\\x=4\ radians[/tex]
