1. ## [SOLVED] Area help

A = /360 x r²

If A= 15m² and = 90° . Find r

The shape is a sector

2. Originally Posted by wato
A = /360 x r²

If A= 15m² and = 90° . Find r

$\displaystyle A=\frac{\theta}{360^{\circ}}\times \pi r^2$

They give you A and $\displaystyle \theta$...

So plugging them into the equation, you have

$\displaystyle 15~m^2=\frac{90^{\circ}}{360^{\circ}}\times \pi r^2$

Now just solve the equation for r:

$\displaystyle 15~m^2=\tfrac{1}{4}\pi r^2\implies 60 ~m^2=\pi r^2\implies r=\dots$

Try to figure out the rest.

I hope this helps!

--Chris

3. ## Thanks

Thanks man, that really helped

er, one more question; if i were to have half a circle with the area being 15m² and i needed to find the radius. what would the equation be?

A= r²/2 ?

4. Originally Posted by wato
Thanks man, that really helped

er, one more question; if i were to have half a circle with the area being 15m² and i needed to find the radius. what would the equation be?

A= r²/2 ?
$\displaystyle A=\tfrac{1}{2}\pi r^2$

--Chris