All Pre-Algebra Resources
Example Questions
Example Question #161 : Area
Find the area of a circle with a radius of .
Write the formula for area of a circle.
Substitute the radius.
Example Question #162 : Area
Find the area of a circle with the diameter of .
Write the formula to find the area of a circle.
The radius is half the diameter.
Substitute the radius into the formula.
Example Question #46 : Area Of A Circle
The diameter of a circle is 21. Which of the following is the closest area?
Divide the diameter by two to obtain the radius.
Write the area of a circle.
Substitute the radius and solve. Assume .
The rounded answer is .
Example Question #47 : Area Of A Circle
Find the area of a circle with a circumference of .
Write the circumference formula and substitute the circumference.
Now solve for r by dividing on each side.
Write the formula to find the area of a circle.
Since we solved for the radius in the above calculation, we will substitute that found value into the area formula and solve.
Example Question #41 : Area Of A Circle
Find the area of a circle with a diameter of 12.
First identify the relationship between diameter and radius of a circle. Then, divide the diameter by two to get the radius.
Write the formula for the area of a circle.
Substitute the radius.
Example Question #49 : Area Of A Circle
Find the area of a circle with a diameter of .
Write the formula for the area of a circle.
To obtain the radius, divide the diameter by
Substitute the radius into the area.
Example Question #50 : Area Of A Circle
Find the area of a circle in if the radius is .
Convert to . There are in a foot.
Write the formula for area of a circle and substitute the new radius.
Example Question #51 : Area Of A Circle
Determine the area of a circle with a radius of .
Write the equation to find the area of a circle.
Substitute the radius.
Example Question #52 : Area Of A Circle
Find the area of a circle if the radius is 24.
Write the formula for the area of a circle.
Substitute the radius.
When multiplying two digit numbers together remember to do it in steps.
First multiply , the six will stay in the ones place and the one will be carried to the tens place above the two.
Now multiply four and the two (highlighted in red above) then add the one that was carried over.
This number goes next to the six.
Placing a zero in the ones places signifies that we are in our second step of multiplication. We will multiply the two and four (highlighted in red).
Now we will multiply two and two,
From here add down to get the final product.
Therefore the final area is,
.
Example Question #53 : Area Of A Circle
Find the area of the circle if the radius is .
Substitute the radius into the formula for the area of a circle.
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