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Here we will learn about using the formula \pi r^2 (pi r squared) to calculate the area of a circle given the radius, diameter or the circumference. There are also worksheets based on Edexcel, AQA and OCR exam questions, along with further guidance on where to go next if you’re still stuck.
- Area of a Sector
Area of a sector formula: Area of a sector =...
- Parts of a Circle
What are the parts of a circle? The parts of a circle are...
- Equation of a Circle
Equation Of A Circle. Here we will learn about the equation...
- Arc Length
Arc Length. Here we will learn about calculating arc length...
- Circumference of a Circle
As the diameter of the circle is twice the radius we can...
- Perimeter of a Sector
Perimeter Of A Sector. Here we will learn about calculating...
- Surface Area of a Sphere
Write down the formula. To answer the question we need to...
- Circle Theorems
Here we will learn about circle theorems, including their...
- Area of a Sector
The area of a regular polygon is half its perimeter times the apothem. As the number of sides of the regular polygon increases, the polygon tends to a circle, and the apothem tends to the radius. This suggests that the area of a disk is half the circumference of its bounding circle times the radius.
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The area of a circle when the radius 'r' is given is πr 2. The area of a circle when the diameter 'd' is known is πd 2 /4. π is approx. 3.14 or 22/7. Area (A) could also be found using the formulas A = (π/4) × d 2, where 'd' is the radius and A= C 2 /4π, where 'C' is the given circumference.
The area of circle can be calculated by using the formulas: Area = π x r 2, in terms of radius ‘r’. Area = (π/4) x d 2 , in terms of diameter, ‘d’. Area = C 2 /4π, in terms of circumference, ‘C’.
13 wrz 2015 · The formula you have is incorrect. It should be V = π*r 2 *h. In order, for you to isolate h, you will need to move π*r 2 to the left side. Since π*r 2 is multiplied with h, you need to divide both sides of the equation by π*r 2 (or multiply by 1/ (π*r 2); it's the same thing). V = π*r 2 *h.
6 kwi 2016 · What the formula $A = \pi r^2$ says is that the area of the circle is larger than the area of the square with side $r$ (as you can clearly see by your drawing). More precisely, the area of the circle is the same as the area of the square with side $\sqrt{\pi}\cdot r$ because $(\sqrt{\pi}\cdot r)^2 = \pi r^2$.
