Calculate Circle Radius/Diameter from Surface Area

[magmash]

Hi

How is circular surface area values square rooted ??. I am using this formula r²Xπ=mm2 to calculate the surface area of a circle but i want to know if there is a formula to get back to the diameter or the radius of the circle ?.

example i have a circular surface area of 5.26mm2 and i want the diameter of that value, how do i solve this ?

Thanks in advance

 

[ShayanJ]

$S=\pi r^2 \Rightarrow r^2=\frac{S}{\pi} \Rightarrow r=\sqrt{\frac{S}{\pi}}$

 

[magmash]

$S=\pi r^2 \Rightarrow r^2=\frac{S}{\pi} \Rightarrow r=\sqrt{\frac{S}{\pi}}$

Thanks for the replay Shyan.

a circel with a diameter of 1.29mm 0.645²π = 1.30 The formula you mentioned √s/π gives a value of 0.362.. ?

Could you show me an example, I would be very thanks full

 

[ShayanJ]

Thanks for the replay Shyan.

a circel with a diameter of 1.29mm 0.645²π = 1.30 The formula you mentioned √s/π gives a value of 0.362.. ?

Could you show me an example, I would be very thanks full

Careful boy! Its not $r=\frac{\sqrt{S}}{\pi}$, its $r=\sqrt{\frac{S}{\pi}}$.

 

[magmash]

:DThanks

 

[Mark44]

Hi

How is circular surface area values square rooted ??.

We don't call it "surface area" - just area. Surface area applies to surfaces in three dimensions. For objects in the plane (two dimensions), we talk about the area.

I am using this formula r²Xπ=mm2

The actual formula is $A = \pi r^2$. If r is given in mm., then the units of area will be square millimeters or mm². The formula shouldn't explicitly show units.

to calculate the surface area of a circle but i want to know if there is a formula to get back to the diameter or the radius of the circle ?.

From the equation $A = \pi r^2$, to get the radius, solve for r. To do this, divide both sides of the equation by $\pi$, then take the square root. Once you have the radius r, you can get the diameter using d = 2r.

example i have a circular surface area of 5.26mm2 and i want the diameter of that value, how do i solve this ?

Thanks in advance