wunder beta📐 Using Simple Formulas
Plug numbers into formulas like P = 2(l + w) to find perimeters, areas, and more. Once you can substitute values, one formula works for every rectangle or triangle.
What you’ll learn
- Using Simple FormulaeSubstitute numerical values into simple formulas such as P = 2(l + w) and A = ½bh to calculate perimeters and areas, following the correct order of operations.A formula is a fixed rule that relates quantities. To use one, substitute a number for each letter and evaluate using the order of operations. For a rectangle, P = 2 × (l + w): with l = 8 and w = 5, brackets first give 8 + 5 = 13, then 2 × 13 = 26. For a triangle, A = ½ × b × h: with b = 10 and h = 6, that is ½ × 60 = 30. The same formula works for every shape of its kind — only the numbers change.
Questions this course answers
What does the perimeter of a shape measure?
Perimeter is the total distance around the outside of a shape.
In the formula P = 2 × (l + w), what should you calculate first?
The order of operations says brackets come before multiplication.
Why is one formula so useful?
A formula is a fixed rule; you substitute new values each time.
What is the area of a rectangle that is 6 cm by 4 cm?
Area of a rectangle is length × width: 6 × 4 = 24 cm².
Grounded in trusted sources
- BBC Bitesize — Maths (Key Stage 2/3)
- Khan Academy — Perimeter and area
- NRICH (University of Cambridge)
- Britannica
Every Wunder lesson is built from real, reputable sources — never invented.
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