How to find the area of a circle with the circumference?

1 answer:

5 0

You can abuse the fact that PI is Circumference/diameter.

This means that, to find the diameter, you would have to do the following:

PI = circumference/diameter
(You can choose the number of decimals of PI, based on how accurate you want the diameter. 3.14 tends to work for most cases.)

After youve done this, you would be able to find the diameter like this:
PI*diameter = circumference
diameter = Circumference/pi

Then, you can use the diameter/2 to find the radius, like this:
radius = diameter/2

After this, you can simply use the formula for the surface area of a circle, like this:

SA = PI*Radius^2

I might be able to add an example, if really needed.

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The oven tray is 600mm by 500mm. A cake tin is 25cm in diameter. How many cake tins can jenny fit on the oven tray at one time?

vlada-n [284]

Area of Circle= $\pi 
$ $r^{2}$
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= 490.87 $cm^{2}$

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= 3000 $cm^{2}$

: . # tin that can hold on bake tray= 3000 $cm^{2}$ / <span>490.87 $cm^{2}$ = 6.11
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3 years ago

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snow_tiger [21]

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2 years ago

We draw 2 cards from a deck of 52 cards. what is the probability that both are queens?

solniwko [45]

Use combination
There are 4 queen cards in a deck of 52 cards
Probability = 4C2 / 52C2

I calculate 4C2 first
4C2 = 4! / (2! 2!)
4C2 = (4 × 3 × 2 × 1) / (2 × 1 × 2 × 1)
4C2 = 6

Then I calculate 52C2
52C2 = 52! / (50! 2!)
52C2 = (52 × 51)/2
52C2 = 1.326

Hence, the probability is
Probability = 4C2 / 52C2
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IRINA_888 [86]

Answer:

a = 12

b = 2

c = 11

Step-by-step explanation:

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3 years ago