Question

The common initial point of the two rays is called _____ of an angle.
(A) Vertex
(B) Arms
(C) Collinear points
(D) Non collinear points

Answer 1

Hint: We solve this question by first going through the definition of a ray. Then we assume two rays $\overrightarrow{AB}$ and $\overrightarrow{AC}$ that intersect at the point A and make a figure of it and discuss the concept of the intersection of rays and what the rays are called as and what their intersection point is called as and mark the appropriate answer.

Complete step by step answer:
Let us start solving this question by first discussing the definition of a Ray.
A Ray is a line with one starting point and without an endpoint, that is it goes to infinity. A Ray looks like below.

So, in the above figure the line starts at point A and passes through point B and then continues without end. So, it is a ray and it is denoted as $\overrightarrow{AB}$.
We are asked to find what the common point of the two rays is called as.
Let us assume the two rays as $\overrightarrow{AB}$ and $\overrightarrow{AC}$. It looks like as below.

Here rays $\overrightarrow{AB}$ and $\overrightarrow{AC}$ intersect at point A.
In the above figure the rays $\overrightarrow{AB}$ and $\overrightarrow{AC}$ are known as the arms of the angle A.
The point of intersection of rays that is the point A is known as the Vertex.

So, the correct answer is “Option A”.

Note: The common mistake one makes here is one might mark the answer as non- collinear points. But the definition of non-collinear points is that the points do not lie on the same line.

Here in the diagram we have considered, the points A, B and C are non-collinear points. But in the question, we are asked about the common point which in this case is point A.