Given that sinx = 0.4, what is tanx? Explain the steps you used

sin(x)=0.4=4/10=2/5

We can assume that the hypotenuse is 5k and the opposite side of angle x is 2k for any real number k(that is not 0) since 2k/5k=2/5

We can find the 3rd side(the adjacent side) by the Pythagorean theorem. sqrt(5k^2-2k^2)=k*sqrt21

Now, tan(x) is the opposite side over the adjacent side so the right side would be 2k/sqrt21*k, now simplify and rationalize the fraction.

2k/sqrt21*k=2/sqrt21=2*sqrt21/21

Done!

Hope this helped any questions can be asked in the comments and I will come answer.

what is the original number? you forgot to add it.