# Thread: Weird Trig problem about exact values of sin, cos, and tan

1. ## Weird Trig problem about exact values of sin, cos, and tan

In this assignment of mine, I'm given an isosceles triangle with sides A, B, and C and <ACB = 90 degrees.

It's an isoceles triangle, so the other two angles are 45 degrees each. But then the problem says "Find the exact values of sin A, cos A, and tan A, based on geometric principles; do not use a calculator."

How do I go about answering this? According to my calculator, sin(45) and cos(45) = .707, while tan(45) = 1--great, so now what? How would I go about figuring that out without a calculator...?

In this assignment of mine, I'm given an isosceles triangle with sides A, B, and C and <ACB = 90 degrees.

It's an isoceles triangle, so the other two angles are 45 degrees each. But then the problem says "Find the exact values of sin A, cos A, and tan A, based on geometric principles; do not use a calculator."

How do I go about answering this? According to my calculator, sin(45) and cos(45) = .707, while tan(45) = 1--great, so now what? How would I go about figuring that out without a calculator...?
http://id.mind.net/~zona/mmts/miscel...90/t454590.gif

Those are the ratios. Use sin(45) to say (Side adjacent)/(Hypotenuse).

3. Originally Posted by WhoCares357
http://id.mind.net/~zona/mmts/miscel...90/t454590.gif

Those are the ratios. Use sin(45) to say (Side adjacent)/(Hypotenuse).
Thanks, that really helps--I'm not sure why I didn't make the connection that .707 was the square root of 1.

$.707 = \dfrac{1}{\sqrt{2}} = \dfrac{\sqrt{2}}{2}$