old guy looking for info please, pi?

Area:
The area of a circle can be found by multiplying pi ¶ (which is 3.14) by the square of the radius
If a circle has a radius of 4, its area is 3.14*4*4=50.24
If you know the diameter, the radius is 1/2 as large.

Circumference:
The circumference of a circle can be found by multiplying pi ¶ by the diameter of the circle.
If a circle has a diameter of 4, its circumference is 3.14*4=12.56
If you know the radius, the diameter is twice as large.

pi = 3.14159265
r= radius

circumference = 2*Pi*R
Area= Pi*R*R (R^2)

c = πd or 2πr
[circumference = pi * diameter or 2 * pi * radius]

a = πr^2
[area = pi * radius * radius]

Answer: A = π r² and C = 2 π r ..... r ≡ radius and π ≅ 3.141592654

Remember that pi is a number that goes on for ever, so any answer using 22/7 or 3.14 or whatever is an approximation. It depends on how accurate you want your answer to be.

π , pronounced pie , = 22/7 and is approx. 3.14

A = π r ² where r is the radius
C = 2 π r

area=pi x radius squared. circumference= diameter x pi

for area = (pi)r^2
= 22/7 x r x r

for circumference = 2(pi)r
= 2 x 22/7 x r


in case u didnt know,r is radius

area=pi*r*r.
circumference=2*pi*r.
pi=(22/7).

3.14 is Pi

circumfrence,

Pi R squared.

3.14 X radius and square it, basically double it.