Question

find the missing side.
z
28°
15
$cos(28^circ) = \frac{15}{z}$
$z = ?$

Explanation:

Step1: Rearrange the formula

Given \(\cos(28^\circ)=\frac{15}{z}\), we can rearrange it to solve for \(z\) by cross - multiplying. So we get \(z\times\cos(28^\circ)=15\), and then \(z = \frac{15}{\cos(28^\circ)}\).

Step2: Calculate the value

We know that \(\cos(28^\circ)\approx0.8829\) (using a calculator to find the cosine of \(28^{\circ}\)). Then substitute this value into the formula for \(z\): \(z=\frac{15}{0.8829}\approx17.0\) (rounded to one decimal place).

Answer:

\(z\approx17.0\) (If we want a more precise value, using a calculator with more decimal places for \(\cos(28^{\circ})\), for example, \(\cos(28^{\circ})\approx0.8829475929\), then \(z = \frac{15}{0.8829475929}\approx16.99\approx17.0\))