GED Math : 2-Dimensional Geometry

Study concepts, example questions & explanations for GED Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #151 : Geometry And Graphs

Determine the area of a circle with a radius of .

Possible Answers:

Correct answer:

Explanation:

Write the formula for the area of a circle.

Substitute the known radius.

The answer is:  

Example Question #151 : Circles

You have a giant gong that has a diameter of . Find the area of the gong.

Possible Answers:

Correct answer:

Explanation:

You have a giant gong that has a diameter of . Find the area of the gong.

To relate radius and diameter, use the following formula:

So, to find our radius from our diameter, divide by 2:

Next, recall the following formula for area:

So, plug in our radius and solve.

Making our answer:

Example Question #151 : Geometry And Graphs

If the circumference of a circle is , what is the area of the circle in square inches? Use .

Possible Answers:

Correct answer:

Explanation:

Recall how to find the circumference of a circle.

, where  is the radius. 

Plug in the given circumference and solve for the radius.

Next, recall how to find the area of a circle.

Plug in the given radius to find the area.

Example Question #154 : Geometry And Graphs

While doing your homework, you become distracted by the 3 holes on the margin of your paper. You estimate that the holes have a diameter of 2.5 cm. What is the area of the circles?

Possible Answers:

Correct answer:

Explanation:

While doing your homework, you become distracted by the 3 holes on the margin of your paper. You estimate that the holes have a diameter of 2.5 cm. What is the area of the circles?

To find the area of a circle, we first need to find our radius:

Next, use the following formula to find the area:

So our answer is 

Example Question #151 : Circles

You have a circular desk which you study at. If the desk has a radius of 2.5 ft, what is its area?

Possible Answers:

Correct answer:

Explanation:

You have a circular desk which you study at. If the desk has a radius of 2.5 ft, what is its area?

Find the area of a circle with the following formula:

We know the radius is 2.5 ft, so plug and solve.

So our answer is 

Example Question #156 : Geometry And Graphs

Give the area of a circle with circumference .

Possible Answers:

Correct answer:

Explanation:

The radius of a circle can be determined by dividing its circumference by :

Set  and evaluate :

Now substitute 11 for  in the area formula for a circle:

 square untis.

Example Question #152 : Geometry And Graphs

Find the area of a circle given that it's circumference is .

Possible Answers:

Correct answer:

Explanation:

In order to find the area of a circle, we must know the formula that will give us the appropriate answer. The area of a circle is , where r is the radius. 

However, the problem doesn't give us radius. The only value provided is the circumference. The formula for circumference is , where d is diameter. So what is the relationship between these two formulas? Since the diameter of a circle is twice the radius, we can see that the relationship helps us find r to solve for the area. 

The circumference equation can be rewritten as 

In order to solve for the radius, we must substitute in the circumference value provided. This will allow us to solve for r. 

Now that we know that value of r, the area can be solved for. 

Example Question #153 : Geometry And Graphs

Find the area of a circle given that it's circumference is .

Possible Answers:

Correct answer:

Explanation:

In order to find the area of a circle, we must know the formula that will give us the appropriate answer. The area of a circle is , where r is the radius. 

However, the problem doesn't give us radius. The only value provided is the circumference. The formula for circumference is , where d is diameter. So what is the relationship between these two formulas? Since the diameter of a circle is twice the radius, we can see that the relationship helps us find r to solve for the area. 

The circumference equation can be rewritten as 

In order to solve for the radius, we must substitute in the circumference value provided. This will allow us to solve for r. 

Now that we know that value of r, the area can be solved for. 

Example Question #154 : Geometry And Graphs

What is the area of a circle if it has a circumference of ?

Possible Answers:

Correct answer:

Explanation:

In order to find the area of a circle, we must know the formula that will give us the appropriate answer. The area of a circle is , where r is the radius. 

However, the problem doesn't give us radius. The only value provided is the circumference. The formula for circumference is , where d is diameter. So what is the relationship between these two formulas? Since the diameter of a circle is twice the radius, we can see that the relationship helps us find r to solve for the area. 

The circumference equation can be rewritten as 

In order to solve for the radius, we must substitute in the circumference value provided. This will allow us to solve for r. 

Now that we know that value of r, the area can be solved for. 

Example Question #155 : Geometry And Graphs

Find the area of a circle, given that it's diameter is 

Possible Answers:

Correct answer:

Explanation:

In order to find the area of a circle, we must know the formula that will give us the appropriate answer. The area of a circle is , where r is the radius. 

However, the problem doesn't give us a value for the radius. The only value provided is the diameter. The formula for diameter is , where d is diameter and r is radius. Using this relationship will help us find r so we can solve for the area. 

Now that we know that value of r, the area can be solved for. 

Learning Tools by Varsity Tutors