The unit circle's radius is one.............but radii are arbitrary.......u can assign any value to them......if u had a radius of the square root of two.....which is about 1.4.........the 1st zero is at 1/2 + 14..i..........1.4 * 10 is 14.................

So the area of a circle whose radius is the square root of 2...........would be 2 pi.....cut that in half.........and u would have pi...................any half circle...........180 degrees of a circle whose radius is the square root of 2................would have an area of pi.......b/c the whole circle has an area of 2pi........

Circle

Solve for 

area

A

=

π

r

2

r Radius

Area of a circle (video) | Khan Academy

▶ 4:01

https://www.khanacademy.org/...area.../area...circle/.../area-of-a-circ...

Area of a circle. ... The area of a circle is pi times the radius squared (A = π r²). Learn how to use this formula to ...

Area of a circle (practice) | Khan Academy

https://www.khanacademy.org/math/basic-geo/...area.../area...circle/e/area_of_a_circle

Find the area of a circle given its radius, diameter, or circumference.