The area of a circle

A FULL LESSON on the area of a circle. (UPDATED)

Assumed prior knowledge:

• Rounding with significant figures and decimals.
• The circumference of a circle.
• Simplifying expressions.

We are learning about: The area of a circle.
We are learning to: Calculate the area of a circle.

Differentiated objectives:

• Developing learners will be able to calculate the area of a circle given its radius or diameter.
• Secure learners will be able to evaluate the area of a circle in terms of π.
• Excelling learners will be able to solve unfamiliar problems using their knowledge calculating the area of a circle.

Starter: Problem solving task to calculate the area of a pattern involving squares and quarter circles.
Main:

• Animated examples (using the MORPH PowerPoint transition) of splitting the circle into sectors to form a rectangle and derive the formula for the area (Could be used as an activity - see extra below) .
• Two further examples; one, leaving answers as rounded values and the second leaving answers in terms of π.
• Standard questions progressing in difficulty, following on to some problem solving questions (inc. two in context).
  Plenary: Spot the mistake.

Extra:

• Examples provided on printable worksheet. Similar to a bookmark shape, the students find it easy to stick this in on the (I use) left side of the page in their books. It saves time from writing down large amounts of text and drawing diagrams. More time to focus on learning!!
• Printable circles for if you wish to do a discovery activity with your students on deriving the formula. I don’t personally do this as my students have been quite happy to see it on the board.

Any feedback is appreciated!