Intermediate Geometry : Circles

Study concepts, example questions & explanations for Intermediate Geometry

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Example Questions

Example Question #32 : How To Find The Angle Of A Sector

True or false: A  sector of a circle comprises one third of the circle.

Possible Answers:

True

False

Correct answer:

False

Explanation:

A circle includes  of angle measure, so a sector of measure  is  of the circle. Set  - the sector is 

of the circle. The statement is false.

Example Question #33 : How To Find The Angle Of A Sector

Inscribed angle 2

 is the center of the above circle.

True, false, or undetermined: 

Possible Answers:

False

True

Undetermined

Correct answer:

True

Explanation:

 is the center of the circle, so  is a central angle. , so its intercepted arc  also has this measure.

 is an inscribed angle which intercepts , so

Substitute:

Example Question #1 : Chords

The radius of  is  feet and .  Find the length of chord .

12

Possible Answers:

Correct answer:

Explanation:

We begin by drawing in three radii:  one to , one to , and one perpendicular to  with endpoint  on our circle.

12

We must also recall that our central angle  has a measure equal to its intercepted arc.  Therefore, .  Our perpendicular radius actually divides  into two congruent triangles.  Therefore, it also bisects our central angle, meaning that 

12

Therefore, each of these triangles is a 30-60-90 triangle, meaning that each half of our chord is simply half the length of the hypotenuse (our radius which is 6).  Therefore, each half is 3, and the entire chord is 6 feet.

Example Question #2 : Chords

If a chord is  units away from the center of a circle, and the radius is , what is the length of that chord?

Possible Answers:

Correct answer:

Explanation:

Draw a segment perpendicular to the chord from the center, and this line will bisect the chord. Setting up the Pythagorean Theorem with the radius as the hypotenuse and the distance as one of the legs, we solve for the other leg.

  

Since this leg is half of the chord, the total chord length is 2 times that, or 9.798.

Example Question #131 : Circles

If a chord is  units away from the center of a circle, and the radius is , what is the length of that chord?

Possible Answers:

Correct answer:

Explanation:

Draw a segment perpendicular to the chord from the center, and this line will bisect the chord. Setting up the Pythagorean Theorem with the radius as the hypotenuse and the distance as one of the legs, we solve for the other leg.

Since this leg is half of the chord, the total chord length is 2 times that, or 16.

Example Question #132 : Circles

If a chord is  units away from the center of a circle, and the radius is , what is the length of that chord?

Possible Answers:

Correct answer:

Explanation:

Draw a segment perpendicular to the chord from the center, and this line will bisect the chord. Setting up the Pythagorean Theorem with the radius as the hypotenuse and the distance as one of the legs, we solve for the other leg.

Since this leg is half of the chord, the total chord length is 2 times that, or 7.937.

Example Question #133 : Circles

If a chord is  units away from the center of a circle, and the radius is , what is the length of that chord?

Possible Answers:

Correct answer:

Explanation:

Draw a segment perpendicular to the chord from the center, and this line will bisect the chord. Setting up the Pythagorean Theorem with the radius as the hypotenuse and the distance as one of the legs, we solve for the other leg.

Since this leg is half of the chord, the total chord length is 2 times that, or 3.606.

Example Question #134 : Circles

If a chord is  units away from the center of a circle, and the radius is , what is the length of that chord?

Possible Answers:

Correct answer:

Explanation:

Draw a segment perpendicular to the chord from the center, and this line will bisect the chord. Setting up the Pythagorean Theorem with the radius as the hypotenuse and the distance as one of the legs, we solve for the other leg.

Since this leg is half of the chord, the total chord length is 2 times that, or 6.

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

If a chord is  units away from the center of a circle, and the radius is , what is the length of that chord?

Possible Answers:

Correct answer:

Explanation:

Draw a segment perpendicular to the chord from the center, and this line will bisect the chord. Setting up the Pythagorean Theorem with the radius as the hypotenuse and the distance as one of the legs, we solve for the other leg.

Since this leg is half of the chord, the total chord length is 2 times that, or 13.266.

Example Question #8 : How To Find The Length Of A Chord

If a chord is  units away from the center of a circle, and the radius is , what is the length of that chord?

Possible Answers:

Correct answer:

Explanation:

Draw a segment perpendicular to the chord from the center, and this line will bisect the chord. Setting up the Pythagorean Theorem with the radius as the hypotenuse and the distance as one of the legs, we solve for the other leg.

Since this leg is half of the chord, the total chord length is 2 times that, or 4.472.

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