True / False
Warm Up: Circle Basics
Write True or False for each statement.
1. The diameter of a circle is twice its radius.
2. A chord that passes through the center is called the diameter.
3. The circumference of a circle is calculated using the formula 2πr.
4. A tangent to a circle touches it at exactly two points.
5. All radii of the same circle are equal in length.
6. A unit circle has a radius of 2 units.
7. An arc is a part of the circumference of a circle.
Fill in the Blanks
Fill in the Blanks
Choose the correct word from the box to complete each sentence.
1.One full rotation around a circle equals degrees.
2.On the unit circle, the y-coordinate of a point gives the value of the of the angle.
3.On the unit circle, the x-coordinate of a point gives the value of the of the angle.
4.A line segment joining any two points on a circle is called a .
5.The angle subtended at the center by an arc equal in length to the radius is called one .
Quiz (MCQ)
Multiple Choice: Circle and Angles
Circle the correct option.
1. What is the radius of a unit circle?
2. In radians, 180 degrees is equal to:
3. On the unit circle, what is the value of cos 0°?
4. At 90°, the point on the unit circle is:
5. Which formula gives the area of a circle with radius r?
6. The unit circle is centered at:
Label the Diagram
Label the Unit Circle
Look at the numbered picture below and write the correct term for each part in the blanks provided.
1.
2.
3.
4.
5.
6.
Short Answer
Think and Answer
Answer the following in your own words.
1. Explain why the radius of a unit circle is always 1, no matter which angle you measure.
2. A point on the unit circle lies at angle 270°. What are its coordinates, and how did you work them out?
3. How is measuring an angle in radians different from measuring it in degrees?
These are open-ended - there's no single right answer to check.
Written by Lernizy Editorial Team
Updated 27 Aug 2026