Arc CD is [tex]\frac{1}{4}[/tex] of the circumference of a circle. What is the radian measure of the central angle?

A. [tex]\frac{\pi}{4}[/tex] radians
B. [tex]\frac{\pi}{2}[/tex] radians
C. [tex]2 \pi[/tex] radians
D. [tex]4 \pi[/tex] radians



Answer :

To determine the radian measure of the central angle corresponding to an arc that is [tex]\(\frac{1}{4}\)[/tex] of the circumference of a circle, follow these steps:

1. Understand the Relationship Between the Arc and the Circumference: Since arc CD is [tex]\(\frac{1}{4}\)[/tex] of the circumference, this means that the central angle subtended by arc CD would also be [tex]\(\frac{1}{4}\)[/tex] of the total central angle in a circle.

2. Recall the Full Circumference Central Angle: In a circle, the total central angle corresponding to the complete circumference is [tex]\(2\pi\)[/tex] radians.

3. Calculate the Central Angle for Arc CD:
[tex]\[ \text{Central angle for arc CD} = \frac{1}{4} \times 2\pi \text{ radians} \][/tex]

4. Simplify the Expression:
[tex]\[ \frac{1}{4} \times 2\pi = \frac{2\pi}{4} = \frac{\pi}{2} \text{ radians} \][/tex]

Thus, the radian measure of the central angle corresponding to arc CD is [tex]\(\frac{\pi}{2}\)[/tex] radians.

Therefore, the correct answer is:
[tex]\[ \boxed{\frac{\pi}{2} \text{ radians}} \][/tex]