It’s not just necessary in the classroom. Finding the area of 2D shapes is an important skill that proves incredibly handy in life.
Whether you’re sizing up a rectangular floor space to see if there’s enough space for your Xbox or choosing the right carpet lengths for your new living room, knowing how to make the correct calculations can go a long way.
However, these skills are also very necessary for exams! And that’s what we focus on here…
Area of 2D Shapes – What’s Covered
This post explains how to find the area of all the 2D shapes you need to know for GCSE. You aren’t given the formula for any of these shapes so you do need to remember them – consider sticking them up somewhere you will look at them regularly or writing revision cards for them.
We will cover:
- The area of a rectangle
- The area of a triangle
- The area of a parallelogram
- The area of a trapezium
- The area of a circle
Area of a Rectangle
To find the area of a rectangle, we simply multiply the width by the length.
Area = 7 × 1.2
Area of a Triangle
To find the area of a triangle, we multiply the base by the perpendicular height then divide by 2.
Area = (4 × 11) ÷ 2
= 44 ÷ 2
Area of a Parallelogram
A parallelogram is a little trickier than the other shapes. We need to multiply the base by the perpendicular height.
This is the measurement that is at a right-angle to the base of the parallelogram. In this case, 4cm.
Area = 4 × 12
Area of a Trapezium
A trapezium is a shape with one set of parallel sides. There are a few ways to find its area but the most reliable method is to use the formula.
The formula labels the parallel sides as and and the perpendicular height as
Then, the area is:
Some people use this song to remember the formula – it fits to the tune Pop Goes the Weasel.
🎶 Half the sum of the parallel sides,
Times by the difference between them,
That’s the way to calculate,
The area of a trapezium.🎶
Area of a Circle
To find the area of a circle, we need to know the length of the radius. This is the distance from the centre to edge. The area is then π times the radius squared, or A = πr2.
Area = π × 102
= 314.2cm2 (to 1d.p.)
Did you like our post on the area of 2D shapes? If so, you can find more of our blogs here! You can also subscribe to Beyond for access to thousands of secondary teaching resources. You can sign up for a free account here and take a look around at our free resources before you subscribe too.