PrepWisePrepWiseArea of Rectangles & Triangles
Geometry & MeasuresDeep Dive

Why is Triangle Area = ½ × Rectangle?

Part of Area of Rectangles & Triangles — GCSE Mathematics

This deep dive covers Why is Triangle Area = ½ × Rectangle? within Area of Rectangles & Triangles for GCSE Mathematics. Revise Area of Rectangles & Triangles in Geometry & Measures for GCSE Mathematics with 12 exam-style questions and 6 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 3 of 7 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 3 of 7

Practice

12 questions

Recall

6 flashcards

Why is Triangle Area = ½ × Rectangle?

1 Draw a rectangle around any triangle
2 The triangle takes up exactly HALF the rectangle
3 So: Triangle = ½ × (base × height) = ½ × Rectangle

Keep building this topic

Read this section alongside the surrounding pages in Area of Rectangles & Triangles. That gives you the full topic sequence instead of a single isolated revision point.

The Key FormulasWorked Example 1: RectangleWhat is Area?Worked Example 2: Triangle

Practice Questions for Area of Rectangles & Triangles

Which formula gives the area of a rectangle with length l and width w?

  • A. 2(l + w)
  • B. l + w
  • C. l × w
  • D. (1/2) × l × w
1 markfoundation

Explain why the area formula for a triangle uses the perpendicular height rather than the slant height.

2 markshigher

Quick Recall Flashcards

Triangle Area
Area = ½ × base × perpendicular height (A = ½bh)
Rectangle Area
Area = length × width (A = l × w)

Want to test your knowledge?

PrepWise has 12 exam-style questions and 6 flashcards for Area of Rectangles & Triangles — with adaptive difficulty and instant feedback.

Join Alpha

Previous

The Key Formulas

Next

Worked Example 1: Rectangle