To solve this problem, we must remember that vertical angles (angles that are across from one another as <TRS and <VRW are above) have the same measure, they are equivalent. This means that we can set up an equation that sets the measures of these two angles equal to one another, as shown below:
x + 40 = 3x
To solve this equation, we will begin by subtracting x from both sides of the equation so that all of the variable terms are on the right side of the equation.
40 = 2x
Next, we should divide both sides of the equation by 2 so that we can get the variable x alone on the right side of the equation and cancel out its coefficient of 2.
x = 20
Therefore, your answer is x=20 (the first option listed).
Hope this helps!
