INITIAL SIDE OF AN ANGLE
Definition Of Initial Side Of An Angle
Initial Side of an Angle is defined as the ray where measurement of an angle starts.
Example of Initial side of an angle
In the figure, the ray BC is known as the initial side of an angle.
Video Examples:3 - Initial side, terminal side, negative angles
Solved Example on Initial side of an angle
Ques: Find the initial side of the angles shown below
Choices:
A. AB, PQ
B. AB, QR
C. BC, PQ
D. BC, QR
Correct Answer: D
Solution:
Step 1: In the given figures, ray BC and ray QR are the initial sides of the angles as the measurement of both the angles starts from these rays.
Quick Summary
- The initial side is the starting ray of an angle.
- Angle measurement typically starts from the initial side.
- The initial side, along with the terminal side, defines an angle.
🍎 Teacher Insights
Use visual aids and real-world examples to illustrate the concept of the initial side. Emphasize that angle measurement starts from the initial side and moves towards the terminal side.🎓 Prerequisites
- Basic Geometry
- Rays and Lines
- Understanding of Angles
Check Your Knowledge
Q1: Which of the following represents the initial side of angle ∠ABC?
Q2: In a standard coordinate plane, if an angle's initial side lies on the positive x-axis, where is the vertex?
Frequently Asked Questions
Q: How do I identify the initial side of an angle?
A: Look for the ray from which the angle's measurement begins. This is usually indicated by an arrow showing the direction of rotation.
Q: Does the initial side always have to be on the x-axis?
A: No, the initial side can be in any position. The angle is measured relative to that starting position.