All Common Core: 7th Grade Math Resources
Example Questions
Example Question #172 : Plane Geometry
The circumference of a circle is inches. Find the area of the circle.
Let .
First we need to find the radius of the circle. The circumference of a circle is , where is the radius of the circle.
The area of a circle is where is the radius of the circle.
Example Question #1 : Radius
The radius of a circle is 4 cm, what is the area?
The area of a circle is found by: , where r is the radius.
.
The area of the circle is .
Example Question #1 : Plane Geometry
The radius, , of the circle below is 18 units. What is the area of the circle?
square units
square units
square units
square units
Cannot be determined
square units
The formula for the area, , of a circle with radius is:
We can fill in
You could do the arithmetic to get an area of about 1,017.876 square units, but it is ok and more precise to leave it as shown.
Example Question #1 : How To Find The Area Of A Circle
Give the area of a circle with diameter 13.
Half of the diameter 13 is the radius . Use the area formula:
Example Question #25 : Radius
How many times greater is the area of a circle with a radius of 4in., compared to a circle with a radius of 2in.?
The area of a circle can be solved using the equation
The area of a circle with radius 4 is while the area of a circle with radius 2 is .
Example Question #42 : Basic Geometry
Find the area of a circle that has a radius of .
Use the following formula to find the area of a circle:
For the circle in question, plug in the given radius to find the area.
In our particular case the radius is .
When squarring a fraction we need to square both the numerator and the denominator.
Example Question #43 : Basic Geometry
Find the area of a circle that has a radius of .
Use the following formula to find the area of a circle:
For the circle in question, plug in the given radius to find the area.
In this problem the known radius is
Now plug the radius into the area equation.
Therefore we get,
Recall that when a square root is squared you are left with the number under the square root sign. This happens because when you square a number you are multiplying it by itself. In our case this is,
.
From here we can use the property of multiplication and radicals to rewrite our expression as follows,
and when there are two numbers that are the same under a square root sign you bring out one and the other number and square root sign go away.
Example Question #941 : Grade 7
What is the area of a circle with a diameter of , rounded to the nearest whole number?
The formula for the area of a circle is
Find the radius by dividing 9 by 2:
So the formula for area would now be:
Example Question #141 : How To Find The Area Of A Circle
If this circle has a diameter of 12 inches, what is its area?
None of the other answers are correct.
To find the area, we need to determine the radius of the circle first.
The radius is calculated as , where D is the diameter.
Given that the diameter is 12 inches, the radius is , or .
Next, we know that the formula for the area of the circle is .
Using the radius we just found, we can find the area:
Example Question #944 : Grade 7
What is the area of the circle provided?
In order to solve this problem, we need to recall the formula for the area of a circle:
The circle in this question provides us with the radius, so we can use the formula to solve:
Solve: