Could someone help me with this? I have a right angle triangle, 90, 30 and 60 degrees. Say the length of A is 30 inches. What would B and C be? Any help would be appreciated. thank you, johnr.
Could someone help me with this? I have a right angle triangle, 90, 30 and 60 degrees. Say the length of A is 30 inches. What would B and C be? Any help would be appreciated. thank you, johnr.
If you know trigonometry this is easy. If you don't know trig then you have to memorize something. I'll assume you don't know the trig.
You have a 30, 60, 90 triangle. We can construct the ratios of these sides. They are always:
$\displaystyle \frac{a}{c} = \frac{1}{2}$
$\displaystyle \frac{b}{c} = \frac{\sqrt{3}}{2}$
Note carefully that we need to know which angle is opposite which side in order to finish this problem. Without knowing that side a is opposite the 30 or 60 degree angle, I cannot proceed further. (But you should be able to take it from here.)
-Dan
Can't draw that fast Tops!
Ok, let's recall a couple of rules about a 30-60-90 triangle. The hypotenuse is twice the length of the shortest side (the side opposite the 30 degree angle). The side opposite the 60 degree angle is the long side and it is equal to the short side times the sqare root of 3.
Look at my diagram. If the short side is 30 in. That makes the hypotenuse 60 inches, and the other leg $\displaystyle 30\sqrt3$ in.
Drop the perpendicular from the top of an equilateral triangle. The angle is bisected to 30d. By Pythagorean theorem, the perpendicular= .5*3^2. This 30-60-90 triangle is similar to yours. If the base is 30, then the hypotenuse is 60 and the third side is .5*3(^.5)*60=30*(3^.5)