Year 6 · Maths · Shape · Lesson 2
Parts of a circle
Name the parts of a circle, know that the diameter is twice the radius, and solve problems with circles in rows and squares.
17-minute video lesson
Teaching, worked examples and 20 practice questions solved step by step.
Watch free for a monthWhat your child will learn
- Name radius, diameter and circumference
- Use d = 2r
- Find the radius from the diameter
- Solve circle problems
The method
- Radius or diameter?
- Diameter: × 2.
- Radius: ÷ 2.
- Units.
Key words: radius, diameter, circumference, centre, circle.
Worked examples
The first three practice questions from the lesson, with every step.
Question 1
A circle has radius 3 cm. What is its diameter?
- Step 1: Look at the circle
- Step 2: Diameter = 2 × radius
- Step 3: 2 × 3 = 6
Answer: 6 cm
Question 2
A circle has radius 7 cm. What is its diameter?
- Step 1: Look at the circle
- Step 2: Diameter = 2 × radius
- Step 3: 2 × 7 = 14
Answer: 14 cm
Question 3
A circle has radius 10 cm. What is its diameter?
- Step 1: Look at the circle
- Step 2: Diameter = 2 × radius
- Step 3: 2 × 10 = 20
Answer: 20 cm