Question

which name can be used for the 20° angle? ∠etv ∠evn ∠evt ∠nvt after another wind change, the weathervane has turned an additional 20° and stopped at point t. image of a coordinate-like system with points n, s, e, w, v, t and angles 90° and 20°

Explanation:

Step1: Recall Angle Naming Rules

An angle is named by its vertex and two rays (sides). The middle letter in the angle name is the vertex. For the \(20^\circ\) angle, the vertex is \(V\), and the sides are \(VE\) (or \(EV\)) and \(VT\) (or \(TV\)).

Step2: Analyze Each Option

• \(\angle ETV\): Vertex is \(T\), not \(V\) – incorrect.
• \(\angle EVN\): Sides \(EV\) and \(VN\) – angle between \(EV\) and \(VN\) is \(90^\circ\) (right angle), not \(20^\circ\) – incorrect.
• \(\angle EVT\): Vertex \(V\), sides \(EV\) and \(VT\) – matches the \(20^\circ\) angle’s vertex and sides – correct.
• \(\angle NVT\): Sides \(NV\) and \(VT\) – angle between \(NV\) (vertical) and \(VT\) would be \(90^\circ + 20^\circ = 110^\circ\) – incorrect.

Answer:

\(\angle EVT\)