How can we use the concept:
Since the vertex is a point, it is named as all points are, with a single capital letter. For example, consider the following angle:
Point B would be the vertex. The name of this angle is ∠ABC. Angles are generally named with three letters, where the middle letter is the vertex and the two other letters are points that the rays, which form the angle, pass through.
A vertex is also a point where the sides of a polygon meet. The plural of vertex is vertices. Consider the following polygon:
This hexagon has 6 vertices - points A, B, C, D, E, and F.
Sample Math Problems
1. Identify the vertex of the angle.
Solution: The vertex is at T because this is the point at which the two rays meet.
2. Kristal is asked to draw ∠CAT. Which of the following is a correct drawing of this angle?
Solution: The correct answer is A and C. We know the vertex of the angle should be A, because ∠CAT places A in the middle of the letters, indicating it is the vertex. Both answer choices A and C correctly place the vertex at A, allowing the rays to pass through points C and T. Answer B is not correct because it places the vertex at C.
3. Name all the angles with a vertex at F.
Solution: There are 3 angles with a vertex at F: ∠GFH, ∠HFJ, and ∠GFJ. All other angles in the diagram have a vertex at G, H, or J.
4. How many vertices does the following figure have?
Solution: The figure has 7 vertices - seven points at which the sides of the polygon meet.
