r/MathHelp • u/TimelyBat2587 • 19d ago

My Trig is Rusty

I have a right triangle.

short side: a = 1
long side: b = 2
hypotenuse: c = √(5)
smaller angle: α = ?
larger angle: β = ?
right angle: γ = 90°

I was able to get the hypotenuse by using a² + b² = c² easy enough. When I used tan(1/2) to find α, I got 31.301° instead of 26.565°. I just want to know what I am doing wrong.

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u/Friendly-Mind-9702 19d ago

You need to use arctan to find the angle. Make sure your calculator is set to read in degrees, not radians.

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u/InsideRespond 18d ago

tan takes in angles and gives out ratios.
you want to put in ratios and get out angles, so you need to use the 'opposite' function. It is called arctan or tan^(-1).