If you know the length of one of the sides of a right triangle and the size of one of the acute angles, you can determine the length of the other side by applying the tangent. Suppose that for the triangle shown in figure 1-23 you know that angle A measures 3652' and that side b measures 4.00 ft. You want to determine the length of side a. Since

Suppose that for the triangle shown in figure 1-23, you know that angle B measures 5308 and that side a measures 3.00 ft. You want to determine the length of side b. You could do this as previously described by applying

However, the fact that side b is larger than side a means that tan B is larger than 1 (you recall that any angle larger than 45 has a tangent larger than 1).

You know that the cotangent is the reciprocal function of the tangent. Therefore, if

it follows that

A table of natural functions tells you that cot 5308' = 0.74991. Therefore,