A) In circle P, find the length of AB given that the radius r = 7 inches and m APB 4 radians?

1 Answer
Jun 5, 2018

12.73

Explanation:

We want to begin this with a diagram.

Assuming that P is the origin of the circle, we have the following scenario:

enter image source here

r=7

The length AB is the longest side of an isosceles triangle with other side lengths 7. The angle between them on the diagram is theta.

We are told that the angle of APB is 4. The angle of our triangle, theta=2pi-4

From here, we can use the cosine rule.

Zoomed in version of just the triangleZoomed in version of just the triangle

AB^2=7^2+7^2-2*7*7cos(2pi-4)

AB^2=98-98cos(2pi-4)
AB^2=162.06
AB=12.73