Question

Consider right triangle ADEF below.EFDWhich expressions are equivalent to cos(ZE)?

Answer 1

The cosine ratio is given in the form:

$\cos\theta=\frac{adj}{hyp}$

From the triangle in the question, the different sides are labeled with respect to angle E as follows:

$\begin{gathered} hyp=EF \\ opp=DF \\ adj=DE \end{gathered}$

Therefore, the cosine ratio for ∠E will be:

$\cos(\angle E)=\frac{DE}{EF}$

ANSWER

$\begin{equation*} \cos(\angle E)=\frac{DE}{EF} \end{equation*}$