I'm trying to work out this one trigonometry question.. The triangle I'm given is a right angle one. The length of the hypotenuse is unknown, the length of the opposite side is 15cm and the length of the adjacent side is 13cm. I have to find the degree of the angle 'b' that is in between the hypotenuse and the adjacent line. I've been trying to work on it myself and have got this far: Tanb=15/13... tan-1(15/13)=0.85... Now I know that can't be the answer (no angle in the triangle is that small) so where have I gone wrong?

Question

I'm trying to work out this one trigonometry question..  The triangle I'm given is a right angle one. The length of the hypotenuse is unknown, the length of the opposite side is 15cm and the length of the adjacent side is 13cm. I have to find the degree of the angle 'b' that is in between the hypotenuse and the adjacent line. I've been trying to work on it myself and have got this far: Tanb=15/13... tan-1(15/13)=0.85... Now I know that can't be the answer (no angle in the triangle is that small) so where have I gone wrong?

pfenn1 · Answer

|dw:1338167866946:dw|$$\tan (b) = \frac{opp}{adj}=\frac{15}{13}=1.15$$$$\tan^{-1} (1.15)=49.1$$