Trigonometry of the right triangle

Thread Starter


Joined Nov 5, 2011
I'm a new Biomedical Tech student and we're working with Trigonometry of the right triangle right now and I have a problem I can't figure out: If a = x, c = 2x : find the Sine, Cosine and Tangent for angles a and b. How do you determine the value for x?


Joined Jan 28, 2005
This appears to be a homework question. If you can confirm this I will move it to the Homework forum.

How about attaching a scan of your effort to solve the problem so that we can see where you are getting snagged.



Joined Nov 26, 2011
You are focusing on the wrong issue. It doesn't matter what x is. What matters is the ratio of a to c. Sin A = a/c (opp/hyp) or in your case x/2x =>1/2. To find the value of angle A simply use inverse sin of 1/2. You should be aware that sin A = cos B as they are an example of a cofunction. Once you have determined the value of angle A you can use the calculator to find each value (approximated) OR draw the triangle out & use pythagorean's theorem to find the missing side b (letting a = 1 and c= 2 remember everything is proportional) and then you will have the exact values. Obviously, if you want to work with Angle B, it is equal to 90 - Angle A or just use the cofunctions. The big idea in this problem is seeing that Sin A = 1/2.