GED Math : GED Math

Study concepts, example questions & explanations for GED Math

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Example Questions

Example Question #115 : 2 Dimensional Geometry

If the diameter of circle is , what must be the area?

Possible Answers:

Correct answer:

Explanation:

Convert the mixed fraction to an improper fraction by multiplying the denominator with the whole number and adding the numerator.  The denominator stays constant.

Write the formula for the area of a circle.

The radius is half the diameter.

The answer is:  

Example Question #116 : 2 Dimensional Geometry

Sector40

The figure above is a circle.

If the radius of the circle above is 9 in., what is the area of the sector? Round to the nearest hundredth.

Possible Answers:

 

 

 

 

 

Correct answer:

 

Explanation:

To find the area of a sector, you are looking for a percentage of the total circle's area.  Thus, if the angle is  degrees, you are looking for  of a complete circle. 

Given that the radius is  in., you know that the area must be:

The area of the sector is:

or

Example Question #117 : 2 Dimensional Geometry

Sector77

The figure above is a circle.

If the diameter of the circle above is 10 in., what is the area of the sector? Round to the nearest hundredth.

Possible Answers:

 

 

 

 

 

Correct answer:

 

Explanation:

To find the area of a sector, you are looking for a percentage of the total circle's area.  Thus, if the angle is  degrees, you are looking for  of a complete circle. 

Given that the diameter is  in., you know that the radius is  in.  This means that the area must be:

The area of the sector is:

or

Example Question #21 : Area Of A Circle

Find the area of a circle with a radius of 8in.

Possible Answers:

Correct answer:

Explanation:

To find the area of a circle, we will use the following formula:

where r is the radius of the circle. 

Now, we know the radius of the circle is 8in. So, we can substitute. We get

Example Question #22 : Area Of A Circle

Determine the area of a circle with an diameter of .

Possible Answers:

Correct answer:

Explanation:

Write the formula for the area of a circle.

The radius is half the diameter.

The answer is:  

Example Question #121 : 2 Dimensional Geometry

Find the area of a circle with a diameter of .

Possible Answers:

Correct answer:

Explanation:

Write the formula for the area of a circle.

The radius is half the diameter.

Multiply the diameter by .

Substitute the radius.

The answer is:  

Example Question #122 : 2 Dimensional Geometry

Find the area of a circle with a diameter of .

Possible Answers:

Correct answer:

Explanation:

Write the area of a circle.

The radius is half the diameter.

Substitute the radius into the equation.

The answer is:  

Example Question #21 : Area Of A Circle

Circle 1

Give the area of the above circle.

Possible Answers:

Correct answer:

Explanation:

The area  of a circle, given its radius , can be found using the formula

The radius is half the diameter - that is,  - so, substituting, 

or

The diameter of the given circle is 7, so set  in the above formula:

,

the correct area.

Example Question #124 : 2 Dimensional Geometry

Let .

Find the area of a circle with a diameter of 12in.

Possible Answers:

Correct answer:

Explanation:

To find the area of a circle, we will use the following formula:

where r is the radius of the circle. 

Now, we know . We also know the diameter is 12in. We know the diameter is two times the radius, so the radius is 6in. Now, we can substitute. We get

Example Question #121 : Circles

What is the area of a circle with a circumference of ?

Possible Answers:

Correct answer:

Explanation:

Write the formula for the area of a circle.

We will need to find the radius of the circle.

Write the formula for the circumference.

Substitute the circumference.

Divide by  on both sides.

The radius is:  

Substitute this into the area formula.

The answer is:  

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