If the radius of a circle is 10 feet, how long is the arc subtended by an angle measuring 81°?
A) 9π feet
B) 2/9π feet
C)9/5π feet
D) 9/2π feet

Respuesta :

81 degrees
1 degree = 2 pi / 360
81 degrees = 162 pi / 360
=9 pi / 20

L (arc) = radius x angle
= 10 x 9 pi / 20
90 pi /20
9/2 pi : D

The answer is D

Answer:

The length of arc is [tex]L=\dfrac{9}{2}\pi[/tex] feet

D is correct

Step-by-step explanation:

Given: If the radius of a circle is 10 feet and arc subtended by an angle measuring 81°

Formula:

[tex]\theta=\dfrac{\text{Length of arc}}{\text{Radius}}[/tex]

where,

Length of arc = L?

Radius of circle, R= 10 feet

Central angle, Ф=81°

First we will change 81 degree to radian

[tex]Radian = \dfrac{\pi}{180}\times degree[/tex]

In radian [tex]=\dfrac{\pi}{180}\times 81[/tex]

Substitute the value into formula

[tex]\dfrac{\pi}{180}\times 81=\dfrac{L}{10}[/tex]

[tex]L=\dfrac{810}{180}\pi[/tex]

[tex]L=\dfrac{9}{2}\pi[/tex] feet

Hence, The length of arc is [tex]L=\dfrac{9}{2}\pi[/tex] feet