Respuesta :

Question:

A circle has a circumference whose length is 25pi find the length of arc whose central angle 90°

Answer:

The length of arc is 19.625 units

Solution:

Given that,

central angle = 90 degree

Circumference = [tex]25 \pi[/tex]

We know that,

[tex]circumference\ of\ circle = 2 \pi r[/tex]

Therefore,

[tex]25 \pi = 2 \pi r\\\\r = \frac{25}{2} = 12.5[/tex]

The formula for arc length when angle is in degrees is:

[tex]\text{ Arc length } = 2 \pi r \times \frac{\theta}{360}[/tex]

Substituting the given values,

[tex]\text{Arc Length } = 2\times 3.14 \times 12.5 \times \frac{90}{360}\\\\\text{Arc length } = 78.5 \times \frac{1}{4}\\\\\text{Arc Length } = 19.625[/tex]

Thus length of arc is 19.625 units

Answer:

There are 360° in a circle.  So, A 90° central angle cuts off an arc which has length 90/360 = 1/4 of the circumference.

Therefore, length of arc = (1/4)(25π) = 25π/4.  

Step-by-step explanation: