Question

Find the value of x​

Answer 1

Answer:

$\large\boxed{x\approx12.94}$

Step-by-step explanation:

Use cosine:

$\cosine=\dfrac{adjacent}{hypotenuse}$

We have:

$adjacent=4\\hypotenusex\\\alpha=72^o\\\\\cos72^o\approx0.309$

Substitute:

$\dfrac{4}{x}=0.309$

$\dfrac{4}{x}=\dfrac{309}{1000}$             cross multiply

$309x=4000$       divide both sides by 309

$x\approx12.94$