In order to find the diameter of a circle if you have the area is to rearrange the formula for the area of a circle to put diameter as the unknown, like so:
PIE*d = Area of a Circle
d = (Area of a Circle) / PIE
Therefore if the area of your circle is 40cm, 40/PIE = 12.73cm and that's the diameter.
To find the diameter of a circle, you will either need to know the area or its circumference. If you know the area: diameter = 2 x squareroot(area / Pi) If you know the circumference diameter = circumference / Pi
If you do not have the area, what do you have? The radius is half the diamiter The radius is PieR2 Worked backwards if you know the circumfrence.
If you know the circumference of a circle, you can find the radius by dividing the circumference by the value of Pi (3.14159...)
a=3.14xradius squared
Area= Pi r squared
Area of a circle = pi*radius2
Do you know how to find the area of a circle when you know the radius ? Good! Do that. Do you know how to find the area of a square when you know the length of the side ? Good! Do that. Now you have two numbers ... the area of the circle and the area of the square. The problem wants you to find the difference of these two numbers. Do you know how to use subtraction to find the difference of two numbers ? Good! Do that.
A semicircle is 1/2 of a circle. Find the area with the diameter you are given as if you had a whole circle, then divide that answer by 2 to get the area of the semicircle.
Divide the perimiter, or circumference, by pi (3.1415), which is the diamter, then divide that by 2 to get the radius
To find the diameter of a circle, you will either need to know the area or its circumference. If you know the area: diameter = 2 x squareroot(area / Pi) If you know the circumference diameter = circumference / Pi
Area of a circle equals pi r2 Therefore the radius of a circle equals the square root of (area divided by pi).
Knowing the area of a circle which is pi times radius squared will help you to find other properties of the circle
Radius = +sqrt(Area/pi)
To find the circumference of a circle when you know the area, you first need to find the radius of the circle using the formula for the area (area = πr^2). Once you have the radius, you can calculate the circumference using the formula for the circumference (circumference = 2πr).
The only piece of information required to find the area of a circle is the radius of the circle. Once you know the radius of the circle, the area is simply the radius squared multiplied by pi (approximately 3.14).
Divide its circumference by 2*pi which will give the radius of the circle. Area of the circle then is pi*radius squared
It depends on the values you have. The base of a cylinder is a circle. If you know the circle's diameter, half it to find the radius. If you know the circle's circumference, divide by 2pi to find the radius. If you know the circle's area, divide by pi and take the square root to find the radius.