Circumference of a circle - derivation
This page describes how to derive the formula for the circumference of a circle.
Recall that the definition of pi (π) is the circumference c of any circle divided by its diameter d. Put as an equation, pi is defined as
π
=
c
d
Rearranging this to solve for c we get
c
=
π
d
The diameter of a circle is twice its radius, so substituting 2r for d
c
=
2
π
r
If you know the area
Recall that the area of a circle is given by
area
=
π
r
2
Solving this for r
r
2
=
a
π
So
r
=
√
a
π
The circumference c of a circle is
c
=
2
π
r
Answer:
672 square inches
with area, multiply the side(s) by themselves for a single number, or their following numbers for more than 2 numbers.
Example
- 18in x 18in = 324 square inches
- 4in x 2in x 5in x 9in = 360 square inches
hope this helps!
Answer:
10x +17y=c (C is the total cost)
Answer:
Domain: [1, infinity)
Range: All real numbers or (- infinity, + infinity)
Step-by-step explanation:
Hope this helps
