Geometry

[rigadin]

Hi guys,

I have a little question. Just for curiousity I would like to know the formula of how to calculate the area of an oval!!

Thanks

[Klaynos]

[math]A=\pi*a*b[/math]

 

where a and b are the semimajor and semiminor axis.

 

Which is the distance from the middle to the furthest point, and the distance from the centre to the edge at 90degrees from the semimajor axis.

[ajb]

Did you want to know just the formula or how to derive the formula?

 

If the latter, then consult mathworld

[the tree]

Depends on what measurements you already have, if you like then [math]Area=\frac{\pi l h}{4}[/math], or you might want to use calculus. What's the context and what level are you working at?

 

Interestingly, does anyone know the difference between an oval and ellipse, if there is one?

[ajb]

Interestingly, does anyone know the difference between an oval and ellipse, if there is one?

 

I don't think there is a difference.

[the tree]

It seems that the word just suddenly changes from oval to ellipse around the point that you start formalising everything and geometry stops being just an issue of identifying shapes.

[rigadin]

Thanks

[rigadin]

I will actually work in grade 9 maths next year but I would like to learn a bit more than I am supposed to!!!!!

[the tree]

What don't you understand Rigadin? What those words mean, or what your supposed to do with them?

[rigadin]

No I got it. I just didn't understand what the word mean!! But now I do. Correct me if I am wrong: The semimajor axis is like half of the length of the oval and the semimajor axis is like half the length of the height!

Thanks anyway

[the tree]

Close enough, semimajor is half the longest distance across and semiminor is half the shortest distance across (if you think about the words, that's kind of obvious) through the centre in both cases.

 

Although that's only their values, there's a little more to what they actually mean.