Question

What is the measure of 0 ?

Answer 1

Answer:

Option A. 4 radians

Step-by-step explanation:

step 1

Find the circumference of the circle

The circumference is equal to

$C=2\pi r$

we have

$r=5\ cm$

substitute

$C=2\pi (5)$

$C=10\pi\ cm$

step 2

Find the measure of angle $\theta$

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

$\frac{10\pi}{2\pi}=\frac{20}{x}\\\\x=2\pi (20)/10\pi\\\\x=4\ radians$