Class 10 Mathematics | The relation of triangles standing on the same base and lying between the same parallels

Class 10 Mathematics · Area

Triangles on the same base and between the same parallels

Theorem 3 · Five worked proofs

By the end of this lesson you can

📐

State and prove Theorem 3

🔍

Spot a shared base and a pair of parallels in a figure

➕

Add or take away a common triangle in a proof

🧮

Find areas using the three area facts

Triangle ABE: base 8 cm, height 6 cm, area 24 cm²

Triangle ABC: base 8 cm, height still 6 cm because EC // AB

Area of ABC is 24 cm² too

Same base, same height, same area

The notes are free to read in full.

Presenter notes: Today we find out why two very different looking triangles can have exactly the same area, and we prove it.