need a math formula

[len]

Not specific to lighting, but that's where I'll use this.

If I have a right triangle, and I know the length of the base and the height, how do I calculate the degree of the two non-right angles? Wondering if there is a formula already available in Excel but I don't have time to look right now.

[jonliles]

it is an inverse Tangent formula, where:
Tan (angle) = = Opposite / adjancent. in this case, the opposite is your height, and the adjancent is your Base.

to solve for (angle):
(angle)=arctangent*(Height/Base)

In Excel:
ATAN(Height/Base)*180/PI= XX (degrees)

*Excel defaults yto radians, so you need to multiply by 180/PI

OR, use your el-cheapo scientiffic claculator left over from those unnecessary math classes.

[jonliles]

PS: It works for either of the non-right angles. Just swap the numbers to be Nase over Height OR know that the sume of all anlges in a Trianlge add up to 180 degrees.

[starksk]

Found this nifty calculator while googling to remember the formulas from trig oh so long ago.

jonliles beat me to the post of the formulae
______________

~Kirk

[len]

It wasn't working correctly in Lotus (likely a formula error on my part), since I don't have Excel. But I'll just make a small chart that I can print out with 1 foot increments based on that online calculator, which is all the accuracy I need. Thanks for the help.

[jwl868]

Looks like it should just be @ATAN in Lotus.


Differences between Microsoft Excel and Lotus 1-2-3:
http://office.microsoft.com/en-us/ex...997741033.aspx


Joe

[len]

I'll give that a try. There's a @tan formula, but it wasn't giving me anything close the the right numbers. I didn't see @atan.

[tcahall]

Take a look at Openoffice.org You can download a complete, very, very functional version of all of the office applications for free.

Tim.

[len]

Actually, I do have Excel. But it's no big thing. I have all the stuff I need.

[Chris15]

In Excel:
ATAN(Height/Base)*180/PI= XX (degrees)

The neater option would be =DEGREES(ATAN(height/Base))...