### All GMAT Math Resources

## Example Questions

### Example Question #7 : Calculating The Ratio Of Diameter And Circumference

A given circle has a circumference of and a radius of . What is the ratio of the circle's circumference to its diameter?

**Possible Answers:**

**Correct answer:**

For a given circle of circumference and radius , .

Since the radius of a circle is equal to half of the circle's diameter , we can then define as,

.

Therefore, the ratio of the circumference to the diameter of this circles is,

.

### Example Question #1 : Calculating The Ratio Of Diameter And Circumference

Find the circumference of a circle with a diameter measuring .

**Possible Answers:**

**Correct answer:**

The circumference of a circle is given by

where

We are told the diameter so we just need to plug in our value into the equation:

### Example Question #1 : Calculating The Length Of A Chord

The chord of a central angle of a circle with area has what length?

**Possible Answers:**

**Correct answer:**

The radius of a circle with area can be found as follows:

The circle, the central angle, and the chord are shown below:

By way of the Isosceles Triangle Theorem, can be proved equilateral, so , the correct response.

### Example Question #2 : How To Graph A Function

The chord of a central angle of a circle with area has what length?

**Possible Answers:**

**Correct answer:**

The radius of a circle with area can be found as follows:

The circle, the central angle, and the chord are shown below, along with , which bisects isosceles

We concentrate on , a 30-60-90 triangle. By the 30-60-90 Theorem,

and

The chord has length twice this, or

### Example Question #1 : Calculating The Length Of A Chord

The chord of a central angle of a circle with circumference has what length?

**Possible Answers:**

**Correct answer:**

A circle with circumference has as its radius

.

The circle, the central angle, and the chord are shown below, along with , which bisects isosceles :

We concentrate on , a 30-60-90 triangle. By the 30-60-90 Theorem,

has half the length of , so

and

The chord has length twice this, or

### Example Question #2 : Chords

The chord of a central angle of a circle with area has what length?

**Possible Answers:**

**Correct answer:**

The radius of a circle with area can be found as follows:

The circle, the central angle, and the chord are shown below:

By way of the Isosceles Triangle Theorem, can be proved a 45-45-90 triangle with legs of length . Its hypotenuse has length times this, or

This is the correct response.

### Example Question #1 : Calculating The Length Of A Chord

The chord of a central angle of a circle with circumference has what length?

**Possible Answers:**

**Correct answer:**

A circle with circumference has as its radius

.

The circle, the central angle, and the chord are shown below:

By way of the Isosceles Triangle Theorem, can be proved a 45-45-90 triangle with legs of length 30. By the 45-45-90 Theorem, its hypotenuse - the chord of the central angle - has length times this, or . This is the correct response.

### Example Question #1 : Calculating The Length Of A Chord

Consider the Circle :

(Figure not drawn to scale.)

If is a angle, what is the measure of segment ?

**Possible Answers:**

**Correct answer:**

This is a triangle question in disguise. We have a ninety-degree triangle with two sides made up of the radii of the circle. This means the other two angles ( and ) must be each.

Use the 45/45/90 triangle ratios to find the final side. Additionally, you could use Pythagorean Theorem to find the missing side.

45/45/90 side length ratios:

Segment

Or, using the Pythagorean Theorem, by rearranging it and solving for , the hypotenuse, which in this case is segment :

### Example Question #101 : Circles

Calculate the length of a chord in a circle with a radius of , given that the perpendicular distance from the center to the chord is .

**Possible Answers:**

**Correct answer:**

We are given the radius of the circle and the perpendicular distance from its center to the chord, which is all we need to calculate the length of the chord. Using the formula for chord length that involves these two quantities, we find the solution as follows, where is the chord length, is the perpendicular distance from the center of the circle to the chord, and is the radius:

### Example Question #1 : Calculating The Length Of A Chord

The chord of a central angle of a circle with circumference has what length?

**Possible Answers:**

**Correct answer:**

A circle with circumference has as its radius

.

The circle, the central angle, and the chord are shown below:

By way of the Isosceles Triangle Theorem, can be proved equilateral, so , the correct response.

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