This heptagon area calculator takes the figures you already have and applies the relationship behind heptagon area calculations for you, giving incircle radius/ apothem (r), circumcircle radius (r) and perimeter from side a, cot, sin, tan and area.
What Is the Heptagon Area Calculator?
The heptagon area calculator works through side a, cot, sin, tan and area to give you incircle radius/ apothem (r), circumcircle radius (r) and perimeter.
It is aimed at the case where you know the method but not the arithmetic: schoolwork, a quick check on a worked example, or a figure that needs to be right first time.
How the Heptagon Area Works
Each step is applied in order and depends only on the values before it, which makes it possible to follow the calculation rather than take it on trust.
If you are working through the same problem by hand afterwards, compare the intermediate values. That is where a mistake usually shows itself.
Checking Your Own Working
Round sensibly as you go and keep the full precision in the calculator. Rounding too early is the most common way of getting a right method to give a wrong answer.
Where a result should be a whole number, such as a count, check it against the constraint that produced it. A fraction of a person is a sign that something upstream needs revisiting.
A Worked Example
Working through an example, with side a set to 10, cot set to 5, sin set to 2, the calculator returns perimeter of 70, and α of 2.24399, and β of 0.8976. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out incircle radius/ apothem (r)?
Enter side a, cot, sin, tan and area. The calculator then works through the relationship and reports incircle radius/ apothem (r), circumcircle radius (r) and perimeter.
What does the heptagon area actually calculate?
It takes side a, cot, sin, tan and area and converts them into incircle radius/ apothem (r), circumcircle radius (r) and perimeter using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter side a?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Can I use this for a quick estimate as well as a precise answer?
Yes. The calculator is built for quick checks, so round your inputs to a sensible number of significant figures and the result will be just as useful. If you need more precision, keep the same method and add digits to the inputs rather than adjusting the method itself.
Does anything you type get stored?
No. The whole calculation runs inside your browser, and nothing you enter is uploaded, logged or sent anywhere.