How to find the area of a circle using its diameter
The formula used to calculate circle area is: A = ? x (o/ 2) 2. Symbols. A = Circle area; ? = Pi = o = Circle diameter; Diameter of Circle. Enter the diameter of a circle. The diameter of a circle is the length of a straight line drawn between two points on a circle where the line also passes through the centre of a circle, or. Jul 28, · The radius begins at the center of the figure and ends at the figure's margin. You can find diameter of a circle by multiplying the radius of a circle by two: Diameter = 2 * Radius Area of a circ.
This post is to explain how to find the area of a circle when its diameter is given, instead its radius. There are two main methods to tk this task. When it comes to find the area of a circlethere are couple of techniques and formulas used for the purpose.
In previous post you have found the information on how to find the area of a circle using its radius in the formula. This post is all about finding the circle area, when we are given with its diameter.
As you know that diameter is the chord of the circle which passes through its center and its the longest chord of the circle too. There are two ways to find the area of circle when its diameter is given. Both methods are explained one by one, on this page.
When the diameter of the tk is given and students want to use it in the formula, then there aa the following formula to find the area of the circle using its diameter. Remember Pi p is a constant whose value is 3. Also, we suggest using only one formula to find the area, which makes the use of the radius of the circle. As we know that radius times 2 is diameter, hence we can calculate radius from diameter by dividing it by 2.
Consider the same above example, but first find the radius from the diameter by dividing it by 2. Notice that the calculated area of the circle is same in both the methods.
We suggest to use the same formula to find the area of a circle which uses radius in it. A circular garden have a diameter of yards. Find the total cost to plant the grass how to use a ledger bookkeeping whole garden.
Use the following worksheet to practice finding area of a circle using its diameter:. Kids can do the following problems to find the circle area, when its diameter is given. Find the area of a circular field whose diameter is 12 yards. What is the area of a clock which have a diameter of 25 cms. The diameter of a dinner plate is 10 inches, find its area. A circle have a diameter of 4 inches, find its area. Use the following worksheet to practice finding area of a circle using its diameter: Finding The Area Of A Circle Using Its Diameter Any one of the above methods can be used to find the areas of circles in each problem.
How to find the area of a what is call center metrics using its diameter This post is to explain how to find the area of thd circle when its diameter is given, instead its radius.
How to calculate the area of a circle? Area of a circle formula
When the diameter of the circle is given and students want to use it in the formula, then there is the following formula to find the area of the circle using its diameter; Consider the letter “d” represents the diameter of the circle, then the area “A” of the circle can be obtained by using the following formula. Consider “r” is the radius of the circle, so we can replace the above area symbol “A” by the formula to find the area of a circle; which is "pi times radius squared", as shown in the next step Hence the diameter of a circle with area equal to 40 square cm is found to be cm. This tool will calculate the diameter of a circle from the area, and will convert different measurement units for area and diameter. Formula. The formula used to calculate the circle diameter is: o = 2 x v(A / ?) Symbols. o = Circle diameter; A = Circle area; ? = Pi = Area of Circle. Enter the area contained within a circle.
Last Updated: April 8, References. This article was co-authored by Grace Imson, MA. Grace Imson is a math teacher with over 40 years of teaching experience. She has taught math at the elementary, middle, high school, and college levels. There are 16 references cited in this article, which can be found at the bottom of the page. This article has been viewed 5,, times. A common problem in geometry class is to have you calculate the area of a circle based on provided information.
The formula is simple and only needs the radius of the circle to find its area. However, you also need to practice converting some other bits of provided data into terms that can help you use this formula. The most common error when using diameter is forgetting to square the denominator. If you don't divide the diameter by 2 to find the radius, you can still find the area of the circle.
However, you need to change the formula so that you square the 'd' otherwise your answer will be wrong. You can find the area of a circle using the radius, the diameter, or the circumference. For example, if the radius of the circle is 6 inches, first you would square 6 and get Therefore, the area of the circle is To find the area using the diameter, or the distance from one side of the circle to the other, first divide the diameter in half to find the radius.
For example, if the diameter is 20 inches, you would divide that in half and get 10 inches. For example, if the circumference is 42 inches, first you would square 42 and get 1, Finally, you would divide 1, by If you want to find the area of a sector from a circle, keep reading the article! Did this summary help you? Yes No. Log in Social login does not work in incognito and private browsers. Please log in with your username or email to continue.
The radius is also one half of the diameter of a circle. The diameter is the line segment that passes through the center and connects opposite sides of the circle. It can be difficult to measure to the exact center of a circle, unless the center is already marked for you on a circle drawn on paper.
For this example, assume that you are told that the radius of a given circle is 6 cm. Square the radius. This variable is squared. Multiply by pi. The true decimal value continues on infinitely. Report your result. If the radius was measured in centimeters, the area will be in square centimeters.
If the radius was measured in feet, the area will be in square feet. If you do not know, then report both. Method 2 of Measure or record the diameter. Some problems or situations will not provide you with the radius.
Instead, you may be given the diameter of a circle. If the diameter is drawn into your diagram, you can measure it with a ruler. Alternatively, you may just be told the value of the diameter. Assume for this example that the diameter of your circle is 20 inches.
Divide the diameter in half. Remember that the diameter is equal to double the radius. Therefore, whatever value you are given for the diameter, cut it in half and you will have the radius.
Use the original formula for area. Report the value of the area. Recall that your area is to be reported in square units. In this example, the diameter was measured in inches, so the radius is in inches. Therefore, the area will be reported in square inches.
You can also provide the numerical approximation by multiplying by 3. This will give a result of 3. Method 3 of Learn the revised formula. If you know the circumference of a circle, you can use a revision of the formula for the area of a circle. This revised formula uses circumference directly, without the radius, to find area. Measure or record the circumference. In some real world situations, you may not be able to measure the diameter or radius accurately.
If the diameter is not drawn for you or the center is not identified, it can be difficult to approximate the center of a circle. For some physical circles - a pizza pan or a frying pan, for example - you may be able to use a tape measure and measure the circumference more accurately than you can measure the diameter.
Use the relationship between circumference and radius to revise the formula. The circumference of a circle is equal to pi times the diameter. Substitute into the formula for the area of a circle.
You can create a modified version of the formula for the area of a circle, using this relationship between circumference and radius. Use the revised formula to solve the area. Using this revised formula, written with the circumference instead of radius, you can use your given information and find the area directly. There is nothing wrong with this.
You should report your area calculation in that term, or you may approximate it by dividing by 3. The area is approximately equal to sq. Method 4 of Identify the known or given information. In some problems, you may be told information about a sector of the circle and then be asked to find the area of the full circle. Find the area of Circle O. Define the chosen sector. The space between these two radii is the sector.
Measure the central angle of the sector. Use a protractor to measure the central angle made by the two radii. Set the base of the protractor along one of the radii, with the central point of the protractor aligned with the center of the circle.
Then read the angle measurement that corresponds with the position of the second radius forming the sector. The problem you are working on should define this for you. The sum of the small angle and the great angle will be degrees. In some problems, instead of having you measure the central angle, the problem may just tell you the measurement.
Use a modified formula for area. Enter the values that you know and solve the area.