Basic Math Examples

Find the Circumference circle (4)
r=4
Step 1
The circumference of a circle is equal to Pi π times the diameter d.
π(diameter)
Step 2
Since the diameter d is equal to 2 times the radius r, the formula for circumference using radius is 2πr.
2π(radius)
Step 3
Substitute the value of the radius r=4 into the formula for the area of a circle. Pi π is approximately equal to 3.14.
2π4
Step 4
Multiply 4 by 2.
8π
Step 5
The result can be shown in multiple forms.
Exact Form:
8π
Decimal Form:
25.13274122
r=4
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π
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4
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 [x2  12  π  xdx ]