No numbers can describe the area of a circle.
However, any number with a square unit of some sort attached can, eg:
1 square units, 2 square units, 345,432 square units, 3,467,235 square units, 56 square miles, 27 acres, 22 square kilometres, 37 hectares, ...
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.
the radius is from the center of the circle to the edge so that's how you find the radius.
You do not need to estimate it. You can calculate it as being pi*r2 which, in this case is pi square cm.
A circle can have a unit of length which could be either a measure of its diameter or radius, or of its circumference. Or the circle could have the unit of area.
There are many things that the numbers 816 could represent. The numbers could represent an area code for telephones numbers in a certain area of the United States.
The area of a circle is the number of square units inside that circle, if each square in the circle to the left has an area of 1cm2, you could count the total number of squares to get the area of this circle. However, it is easier to use one the following formulas; A=.r²or A=pi times r times r, where A is the area and r is the radius.
Divide the change by the initial number to get a fraction and multiply by 100% to get a percent. The percent you get will describe the change in area in the mathematical language of numbers.
well..... it could be the area of a circle and many other things (well shapes)
There is no way to find the exact area of a circle. The formula for the area is Pi times the radius squared. But Pi is an irrational number -- that is, no matter how many numbers you write it out to, you could always write it further. Since there is no exact value of Pi there can be no exact value of the area based on the diameter. The radius is half that of a diameter. Therefore, if you know the diameter you know the radius. In this case the radius is 3cm and the area of the circle = pi * 32 So the answer is roughly
Area of a circle = pi*radius2
Area of a circle = Pi * radius2