The example below illustrates clearly how to find the radius of a circle when the circumference is known. Suppose the circumference of a circle is 50.24 inches, calculate r.
Solution
Here are the steps to follow:
Step 1:
Write down the circumference formula.
Step 2:
Replace the circumference with 50.24 inches.
Step 3
Since you are looking for r, you need to get rid of 2 × pi. You do this by dividing both sides by 2 × pi.
Step 4
Notice that now the number next to r is just 1 and 1 times r is r. To get the answer, you just have to divide 50.24 inches by 6.28. When the circumference of a circle is 50.24 inches, the radius is 8.
The example above illustrates a simple but long way to solve this problem. You can find the radius of a circle very quickly by dividing the value of any circumference by 6.28.
Example 2:
Find r when the circumference is 31.4
r = 31.4 / 6.28 = 5.
Yes, it is that simple yet you still need to know how to do it by following the steps above.
May 19, 19 09:20 AM
Basic math review game - The one and only math adventure game online. Embark on a quest to solve math problems!
Basic math formulas
Algebra word problems
New math lessons
Your email is safe with us. We will only use it to inform you about new math lessons.
Recommended
Scientific Notation Quiz
Graphing Slope Quiz
Adding and Subtracting Matrices Quiz
Factoring Trinomials Quiz
Solving Absolute Value Equations Quiz
Order of Operations Quiz
Types of angles quiz
May 19, 19 09:20 AM
Basic math review game - The one and only math adventure game online. Embark on a quest to solve math problems!