



 
Hi Tizoc, I'm not sure I understand your question but I'll give it a try. I expect that your textbook or teacher have told you that \[\tan(A) = \frac{\mbox{opposite}}{\mbox{adjacent}}.\] In my diagram of a right triangle, since I am interested in the angle at $A$ the side opposite to $A$ is $BC$ and the side adjacent to $A$ is $CA.$ Suppose that measure of the angle at $A$ is $37^o .$ Suppose you also know that the length of $CA$ is $ 15$ centimeters then \[\tan(37^o) = \frac{\mbox{opposite}}{\mbox{adjacent}} = \frac{BC}{CA} = \frac{BC}{15},\] and hence \[BC = 15 \times \tan(37^o).\] Now it's time to use your calculator. Make sure it is set on degrees and input $\tan(37).$ My calculator gave me $\tan(37) = 0.7536$ and hence \[BC = 15 \times 0.7536 = 11.3 \mbox{ centimeters.}\] Write back if I haven't answered your question,  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 