Hypotenuse

[Arc]

Hi Guys. If I know the length of 2 sides of a right triangle how do I figure out the length of the other side?

Thanks!

[zaza]

You need to know whether they are the two sides at right angles or not. If they are, then square each, add the squares, and then sqrt the answer. If they are not, then square each, take the abs() of the difference and then sqrt the result.

This is Pythagoras' Theorem!!!

zaza

[Arc]

Thank you!

[zaza]

You're welcome. Don't forget to mark it resolved (as you probably know well - you've been here even longer than me!)

zaza

[jemidiah]

If the two sides aren't perpendicular [don't make a right angle], you need to use the law of cosines which is an extension of the Pythagorean Theorem.

The Law of Cosines says that given sides b and c of a triangle, and given the angle between those sides called A, you can find the measure of the third side by using this formula:

a²=b²+c²-2bc*cosA.

This is equal to the Pythagorean Theorem when A = 90 degrees, because cos 90 deg. = 0, and the last term drops out.

[zaza]

Or you can use the sine rule:

sinA/A = sinB/B = sinC/C

...but this is just school maths.



zaza