# angle calculation

• Mar 10th 2008, 01:22 AM
kumar
angle calculation
Hi,

I have to calculate theta in the picture. anyone help me.

Thanks.
• Mar 10th 2008, 02:35 AM
mr fantastic
Quote:

Originally Posted by kumar
Hi,

I have to calculate theta in the picture. anyone help me.

Thanks.

(180 - acute angle) degrees.
• Mar 10th 2008, 08:53 AM
Nacho
Quote:

Originally Posted by kumar
Hi,

I have to calculate theta in the picture. anyone help me.

Thanks.

I think that you should say more information abaout the picture, because i dont know if that fugure is a rectangle o for example, if the line horizontal is middle point... etc
• Mar 10th 2008, 09:13 PM
kumar
Hi
Thanks for ur reply. ie. rectangle only and that horizondal line is in mid point only. for explanation only I drawn that lines.
• Mar 11th 2008, 01:27 PM
Nacho
Quote:

Originally Posted by kumar
Hi
Thanks for ur reply. ie. rectangle only and that horizondal line is in mid point only. for explanation only I drawn that lines.

ok, as your problem havent numbers, theta only can find in function of the other angles, as the picture show, we say that:

$\displaystyle \begin{gathered} \sphericalangle CAB = \alpha \hfill \\ \sphericalangle CBA = \beta \hfill \\ \sphericalangle CBD = \theta \hfill \\ \hfill \\ \alpha + \beta + 90 = 180 \Leftrightarrow \alpha + \beta = 90 \hfill \\ \end{gathered}$

now

$\displaystyle \beta + \theta = 180 \Leftrightarrow \boxed{\theta = 180 - \beta }$

but remember that

$\displaystyle \begin{gathered} \alpha + \beta = 90 \Leftrightarrow \beta = 90 - \alpha \hfill \\ \hfill \\ \therefore \theta = 180 - \beta \Leftrightarrow \theta = 180 - \left( {90 - \alpha } \right) \hfill \\ \boxed{\theta = 90 + \alpha } \hfill \\ \end{gathered}$

I hope that you understand it :)

if you question continue, only post it

P.D: sorry for my bad english
• Mar 12th 2008, 10:55 PM
kumar
Thanks Nacho