Question 1027668
you have a right triangle ABC, where angle B is the right angle.


you know that AB = 5 cm.


you know that angle BAC is 40 degrees.


you want to find the length of BC.


draw the triangle and you will see that BC is opposite angle BAC.


tan(40) is equal to opposite / adjacent.


opposite if BX
adjacent is AB.


if you let x equal the length of BC, then you get:


tan(40) = x/5


solve for x to get x = 5 * tan(40).


solve for x to get x = 4.195498156.


the length of BC is equal to 4.195498156.


this can be rounded as required, but i'll just leave it as what the calculator i used displayed it as.


the diagram i drew is shown below:


<img src = "http://theo.x10hosting.com/2016/040201.jpg" alt="$$$" </>