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:
13,92838827718412ft
Step-by-step explanation:
a² + b² = c²
a = 13ft
b = 5ft
169 + 25 = 194
c = √194
c = 13,92838827718412ft
Answer:
Where's the question?
Step-by-step explanation:
Answer:
0.3(8.2 x 10^-3) = 2.46 X 10 ^ -3
Step-by-step explanation:
We need to solve the equation 0.3(8.2 x 10^-3) and write answer in scientific notation.
Solving,
= 0.3(8.2 x 10^-3)
= 0.3 * 0.0082
= 0.00246
Writing in scientific notation
= 2.46 X 10 ^ -3
So, after solving the expression 0.3(8.2 x 10^-3) the result is 2.46 X 10 ^ -3.
A is 30% more than B. So, A = B + 30% of B = B + 30/100 *B = B + 3/10 *B = 13/10 *B. B is 60% less than C. So, B = C - 60% of C = C - 60/100 *C = C - 3/5 *C = 2/5 *C.
