Posts Tagged ‘radius’

Problem 1097

 

What is the formula for the circumference C of a circle of radius r? What is the formula for area A of a circle of radius r?

 

Solution:-

 

The formula for the circumference C of a circle of radius r is C = 2πr.

The formula for the area A of a circle of radius r is A = πr2.

 

 

Problem 483

 

Write the equation of a circle with a center at (-2, -5) and a radius of 6.5.

 

Solution:-

 

Use the general formula (x – h)2 + (y – k)2 = r2.

 

Where (h, k) are the center and r = radius.

 

(x + 2)2 + (y + 5)2 = 42.25