In the diagram, three line segments intersect as shown.

The value of $x$ is
(A) 40
(B) 60
(C) 80
(D) 100
(E) 120

![](https://cdn.mathpix.com/cropped/2024_04_20_e85ef69091c57cb633f3g-056.jpg?height=320&width=556&top_left_y=810&top_left_x=1164)
The unlabelled angle inside the triangle equals its vertically opposite angle, or $40^{\circ}$.

Since the sum of the angles in a triangle is $180^{\circ}$, then $40^{\circ}+60^{\circ}+x^{\circ}=180^{\circ}$ or $100+x=180$. Thus, $x=80$.

ANSWER: (C)