Your Basket 0 items - £0.00

Students learn how to find the area of various 2D shapes parallelograms, trapezia, compound shapes and circles. Throughout the topic links are made to algebraic reasoning and estimation. This topic takes place in Term 1 of Year 9 and links to volume and surface area later on.

**Prerequisite Knowledge**

- Know and apply formulae to calculate the area of rectangles
- Calculate the perimeters of 2D shapes, including composite shapes;
- Compare and order lengths, mass, volume / capacity and record the results using >, < and =
- Measure, compare, add and subtract: lengths (m/cm/mm); mass(kg/g); volume/capacity (l/ml)
- Identify and apply circle definitions and properties, including: centre, radius, chord, diameter, circumference, tangent, arc, sector and segment

**Success Criteria**

- Know and apply formulae to calculate: area of triangles, parallelograms and trapezia;
- Know the formulae: circumference of a circle = 2πr = πd, area of a circle = πr
^{2}; calculate: perimeters of 2D shapes, including circles; areas of circles and composite shapes; - Calculate arc lengths, angles and areas of sectors of circles

**Key Concepts**

- Demonstrate a triangle as being half a rectangle so students know to use the perpendicular height in their calculation. Demonstrate a parallelogram as having an equal area to a rectangle.
- To calculate the area of composite rectilinear shapes have students break them up in different ways.
- A sector is a fraction of 360° of the entire circle.

**Common Misconceptions**

- Students often confuse area and perimeter.
- When calculating the area of a triangle or parallelogram students tend to use the slanted height rather than the correct perpendicular height.
- Arc length and area of a sector are often rounded incorrectly. Encourage students to evaluate as a multiple of pi and calculate the decimal at the end.

August 22, 2019

When getting ready for a new school year I have a list of priorities to work through. Knowing my team have all the information and resources they need to teach their students gives me confidence we will start the term in the best possible way. Mathematics Teaching and Learning Folder All teachers receive a folder […]

July 6, 2019

Earlier this week, my school took part in a trial OFSTED inspection as part of getting ready for the new inspection framework in September 2019. This involved three Lead Inspectors visiting our school over the course of two days. The first day involved a ‘deep dive’ by each of the Lead Inspectors into Mathematics, English […]

June 30, 2019

The method of how to solve quadratics by factorising is now part of the foundational knowledge students aiming for higher exam grades are expected to have. Here is an example of such a question. Solve x2 + 7x – 18 = 0 In my experience of teaching and marking exam papers students often struggle with […]