Math Help

Question

Math Help

Communist · Answer

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Astro · Answer

Do you know the formula?

xhikari · Answer

my bad i was trying to paste the formula... its A=πr^2

xhikari · Answer

do you know what the radius (r) is? if not I can show you how to find it

Astro · Answer

He already has the radius it's 7 so it would be A=3.14*7^2 which equals (rounded) 154.0

Astro · Answer

Does that make sense?

xhikari · Answer

@astro wrote:

He already has the radius it's 7 so it would be A=3.14*7^2 which equals (rounded) 154.0

actually its half of that because 7 is the diameter

xhikari · Answer

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Astro · Answer

Oh yeah my bad, so A=3.14*3.5^2

Astro · Answer

So I think if A=3.14*3.5² it should equal something around 38.4 cm²

xhikari · Answer

@astro wrote:

So I think if A=3.14*3.5² it should equal something around 38.4 cm²

i agree : )

helpandlearnandchat · Answer

$$A=\pi r^2 \ \r = \frac{1}{2}d\r=3.5\\pi(3.5)^2 = 34.48$$
You cannot use 3.14 because it's not exactly pi
So, you got the wrong answer, since 34.48 rounds to 34.5 cm^2

xhikari · Answer

@helpandlearnandchat wrote:

$$A=\pi r^2 \ \r = \frac{1}{2}d\r=3.5\\pi(3.5)^2 = 34.48$$ You cannot use 3.14 because it's not exactly pi So, you got the wrong answer, since 34.48 rounds to 34.5 cm^2

it is impossible to use exactly pi because it is never-ending so the common substitution is 3.14

helpandlearnandchat · Answer

@xhikari wrote:

@helpandlearnandchat wrote:

$$A=\pi r^2 \ \r = \frac{1}{2}d\r=3.5\\pi(3.5)^2 = 34.48$$ You cannot use 3.14 because it's not exactly pi So, you got the wrong answer, since 34.48 rounds to 34.5 cm^2

it is impossible to use exactly pi because it is never-ending so the common substitution is 3.14

use a calculator you dumbhead

helpandlearnandchat · Answer

Or actually even if you do use 3.14
3.14(3.5)^2 = 38.46 which still round sto 38.5

so either way, you're wrong

xhikari · Answer

@helpandlearnandchat wrote:

@xhikari wrote:

@helpandlearnandchat wrote:

$$A=\pi r^2 \ \r = \frac{1}{2}d\r=3.5\\pi(3.5)^2 = 34.48$$ You cannot use 3.14 because it's not exactly pi So, you got the wrong answer, since 34.48 rounds to 34.5 cm^2

it is impossible to use exactly pi because it is never-ending so the common substitution is 3.14

use a calculator you dumbhead

some people wont have a calculator on the test. its a lot easier to use 3.14

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