How can you remember area of a circle formula easily?
Time to review your basic concepts! So, to begin with, tell us what is a circle? Thinking probably? Don’t stress over! A circle is a locus of all the points that are equidistant from a central point. In other points, you join several points that are equidistant from a point, which is the central point, to obtain a circle.
Do you know the area of a circle formula? We can hear you saying yes to that. Well, the area of a circle formula is given by A = pi * r * r, where A represents the area of the circle and r represents the radius of the circle.
Now, we’ll learn the same formula but the other way round. Let’s think of a rectangle, whose length is L and breadth is B. What is the area of a rectangle? It’s L * B. If we consider that L = pi * r and B = r, so the area comes out to be pi * r * r, right? Congratulations on your new method of obtaining the area of a circle formula.
How to remember circumference of a circle formula?
After juggling with the area, now it’s time to hang out with the circumference of a circle. Do you remember the circumference of a circle formula? We again hear some positive noise like we did in case of the area. The circumference of a circle can be found out by the formula C = 2 * pi * r, where C denotes the circumference of the circle and r represents its radius.
We can work with one more formula, which is mentioned below:
Area = (Circumference / 2) * r, in symbolic notation, we can write this formula as A =(C / 2) * r, where the symbols have their usual meanings. By remembering this one expression, you can work with both the area and circumference of a circle at once.
Example: A circle of radius 9 units stretches over a play ground of 54 sq units’ area. Find the circumference of the circle?
Solution: By using the above-mentioned standard formula, we can put the given values as shown below:
54 = (C / 2) * 9 => C = 12.
Thus, you can remember this standard formula for working with both the area of a circle formula and circumference of a circle formula.