All Pre-Algebra Resources
Example Questions
Example Question #11 : Perimeter
Find the circumference of the circle with a diameter of .
Write the formula for the circumference of a circle.
Substitute the diameter.
Example Question #12 : Perimeter
Find the circumference of a circle with an area of 5.
Write the formula for the area of a circle.
Substitute the area to find the radius.
In order to solve the equation, we have to isolate the variable. We do this by performing the same operation to either side of the equation.
Write the formula to find the circumference of the circle.
Substitute the radius.
Example Question #12 : Circumference Of A Circle
If find the circumference of a circle with a diameter of 10 inches.
To solve, we will use the formula for circumference of a circle. The formula is
where . We know that the diameter of the circle is 10 inches. To find the radius, we simply divide by 2.
Therefore,
We know , so we will substitute. We get
Therefore, the circumference of the circle is 31.4 inches.
Example Question #13 : Perimeter
Find the circumference of a circle with a radius of 6cm.
The formula to find the circumference of a circle is
where d is the diameter. We know the radius is 6cm. We also know to find the diameter, we take two times the radius. Therefore, the diameter is 12cm. So, substituting into the formula, we get
or
Therefore, the circumference of the cirlce is .
Example Question #15 : Circumference Of A Circle
A circle has a radius of . What is its circumference?
Not enough information given
The formula for the circumference of a circle is
.
So, we simply plug in the radius of in order to solve for the circle's circumference:
Therefore, the circumference of ths circle is .
Example Question #16 : Circumference Of A Circle
What is the distance around a silo, if the distance from the center of the silo to the outside is ?
What is the distance around a silo, if the distance from the center of the silo to the outside is ?
Picture a silo, its base is a circle.
This problem want the circumference of that circle. It gives us the distance from the center to the outside of the circle, aka the radius.
Find circumference via the following formula:
So the distance is:
Example Question #12 : Perimeter
Alfredo ran laps around his track. He had just learned in math about circumference and was wondering what the circumference of his circular track was. He knows that the diameter of his track is 100 feet. What is the circumference of Alfredo's track?
None of the above
The only thing that needs to be known for this question is the equation for circumference which is:
Therefore your answer to this problem is simply
Example Question #13 : Perimeter
Susy's yard is 32 yards by 17 yards. What is the total perimeter of her yard?
Recall, the perimeter of a rectangle = 2*length + 2*width
Using the values given to us in the problem:
Thus, the perimeter is 98 yards.
Example Question #2 : Perimeter Of A Rectangle Or Square
Sally has a rectangular garden that is surrounded by a 6ft-wide and 8ft-long fence. However, she wants to expand her garden so that it is twice as wide and twice as long. What is the new perimeter of her garden?
We know the original garden is a 6ft by 8ft rectangle. sally wants to expand her garden so that the new rectangle is twice as long and twice as wide, so the new dimensions are 12ft by 16ft.
The perimeter of a rectangle with these dimensions is
12*2 +16*2 = 56.
Example Question #3 : Perimeter Of A Rectangle Or Square
Choose the correct equation to solve for the perimeter of the rectangle.
Peter's backyard is a rectangle. Two sides of his lawn are feet long, and two sides of his lawn are feet long.
The correct answer is
Rectangles have sets of equal sides. In this example, one set of these sides is feet long and one set is feet long.
Therefore, multiplying the length of each side by two then adding these together will produce the perimeter.