Basic Shape Areas

You'll use these three formulas constantly in your maths lessons, so getting them sorted now will save you loads of time later.

For squares and rectangles, it's dead simple: just multiply the base by the height. A square with 5cm sides? That's 5 × 5 = 25cm². A rectangle that's 8cm by 3cm? That's 8 × 3 = 24cm².

Triangles need a slightly different approach because they're basically half of a rectangle. Take the base, multiply by the perpendicular height, then divide by 2. So a triangle with a 6cm base and 4cm height gives you (6 × 4) ÷ 2 = 12cm².

Quick Tip: Always check you're using the perpendicular height for triangles - it's the line that goes straight down from the top to the base, not the slanted side!

Advanced Shape Areas

These shapes might look trickier, but once you know the formulas, they're just as straightforward as the basic ones.

A trapezium has two parallel sides of different lengths. Add those two parallel sides together, multiply by the height, then divide by 2. The formula $a + b$ × height ÷ 2 works every time.

Parallelograms are like rectangles that have been pushed sideways. You still use base × perpendicular height - just make sure you measure the height at a right angle, not along the slanted edge.

For a kite, you're looking at the two diagonals (the lines that cross inside). Multiply the length by the height, then divide by 2 - it's similar to finding a triangle's area.

Exam Success: These formulas usually appear on your exam paper, but practising them now means you won't waste precious time looking them up during tests!