### Home > GC > Chapter 11 > Lesson 11.1.1 > Problem 11-18

11-18.

In a circle, chord has length

*. What is the area of the circle? Draw a diagram and show all work.*

The measure of the intercepted arc is equal to the central angle.

, because both are radii, so

Isosceles triangles have equal base angles, so

but

so

Because the angles are all equal, the triangle is equilateral.

So the radius () is