Question

Question was provided via image upload.

Explanation:

Step1: Sum angles to 360°

The total around point $F$ is $360^\circ$, including a right angle.
$$(x+4)^\circ + (x+4)^\circ + (x+4)^\circ + 90^\circ = 360^\circ$$

Step2: Simplify the equation

Combine like terms.
$$3(x+4) + 90 = 360$$

Step3: Isolate the variable term

Subtract 90 from both sides.
$$3(x+4) = 360 - 90 = 270$$

Step4: Solve for $(x+4)$

Divide both sides by 3.
$$x+4 = \frac{270}{3} = 90$$

Step5: Solve for $x$

Subtract 4 from both sides.
$$x = 90 - 4 = 86$$

Answer:

$86$