find de. write your answer as an integer or as a decimal rounded to the nearest tenth. de =

Answer:

$6.7$

Explanation:

Step1: Identify trig - ratio

In right - triangle $CDE$, $\cos D=\frac{DE}{CD}$.

Step2: Substitute values

We know that $CD = 9$ and $\angle D=42^{\circ}$. So $DE = CD\times\cos D$.

Step3: Calculate

$DE=9\times\cos42^{\circ}$. Since $\cos42^{\circ}\approx0.7431$, then $DE = 9\times0.7431 = 6.6879\approx6.7$.