Find the value of x, given that the angles shown are supplementary.

The image shows three angles, $x$, $5x$, and $4x$, that lie on a straight line. Angles on a straight line are supplementary, meaning their sum is $180^\circ$.

Add the three angles and set their sum equal to $180^\circ$:

Combine the like terms on the left side of the equation:

Divide both sides by 10 to find the value of $x$:

Substitute the value of $x$ back into each expression:

• First angle: $x = \boxed{18^\circ}$
• Second angle: $5x = 5 \times 18^\circ = \boxed{90^\circ}$
• Third angle: $4x = 4 \times 18^\circ = \boxed{72^\circ}$