ACT Math : Chords

Example Questions

Example Question #1 : How To Find The Length Of A Chord

In the figure below,  and  are radii of the circle. If the radius of the circle is 8 units, how long, in units, is chord ?

Explanation:

The radii and the chord form right triangle . Use the Pythagorean Theorem to find the length of .

Example Question #2 : How To Find The Length Of A Chord

A circle has a maximum chord length of  inches. What is its radius in inches?

Explanation:

Keep in mind that the largest possible chord of a circle is its diameter.

This means that the diameter of the circle is inches, which means an -inch radius.

Remember that ,

Example Question #3 : How To Find The Length Of A Chord

In the circle with center A, shown below, the length of radius  is 4 mm. What is the length of chord  ?

Explanation:

In order to solve this question, we need to notice that the radii of the circle and chord  form a right triangle with  as the hypotenuse. We can use the Pythagorean theorem to find chord .