1. Areas of Flags 3

2. Starter
10cm
To the left is the flag of Jamaica. The area of yellow is 60cm2. Given that the areas of green and black are equal, calculate the heights of the triangles indicated on the diagram…
10cm
8cm
14cm

3. Areas of Flags 3
Learning Objectives All will be able to understand and use the formula for the area of a Trapezium (Level 6) Most will be able to use this formula alongside those for other shapes in answering questions based on flags (Level 6/7) Some will be able to include ratio and more advanced problem-solving skills in today’s questions (Level 7)

4. Area of the Parallelogram
Areas of Flags 3
5cm
8cm
5cm
8cm
8cm
6cm
8cm
5cm
5cm
Copy the original Trapezium
Flip it Upside down
Place it alongside the original one
It is now just a parallelogram!
Area of the Parallelogram
B x H
13 x 6
78cm2
Area of the Trapezium
78 ÷ 2
= 39cm2

5. Areas of Flags 3 General Formula (a + b) x h 2 a a h h b b
a and b are the parallel sides
(a + b) x h 2
h is the perpendicular height

6. Areas of Flags 3
8cm
Calculate the areas of each colour on the flag of Equatorial Guinea based on the information given. You may ignore the emblem in the centre
It IS possible to find all the required lengths but it will require careful thought!
6cm
3cm

7. Plenary

8. Summary Area of a Rectangle Area of a Triangle Area of a Parallelogram
We have seen how to calculate the Area of a Trapezium
We have included this in our recent work on areas of flags
Notice that all the shapes we have looked at so far are all effectively based on the area of a Rectangle
Area of a Rectangle
Area of a Triangle
Area of a Parallelogram
Area of a Trapezium