A Consider that lines A and B are parallel. Which equation models the relationship between 21 and 25?
A)
21 = 25
B)
21+ 25 = 90°
9
21+ 25 = 180°
D)
21+ 25 = 100°

C. 21+ 25 = 180°

Step-by-step explanation:

C is correct

Step-by-step explanation:

The formula for arc length is:

Where Θ is measured in degrees.

We know that the arc length is 8π when the degree is 80. So, substitute 8π for A and 80 for Θ:

Divide both sides by 2π:

Simplify the fraction:

Multiply both sides by 9/2:

So, the radius is 18.

Now, we can find the area of the circle. The formula for the area of a circle is:

Substitute 18 into r:

Simplify:

And we're done!