Class 7 Math: The Triangle and its Properties Quick Revision Chapter Summary

Need to review the entire chapter before a test? This quick revision guide summarizes all the core concepts, topics, and equations taught in Class 7 The Triangle and its Properties to help you refresh your memory instantly.

Core Topics At a Glance

### 📌 Medians and Altitudes of triangles Median joins a vertex to the midpoint of the opposite side. Altitude is a perpendicular line from a vertex to the opposite side.

### 📌 Exterior angle property An exterior angle of a triangle is equal to the sum of its two interior opposite angles.

### 📌 Angle sum property of triangle The sum of the three interior angles of a triangle is always 180°.

### 📌 Equilateral and Isosceles triangle relations Equilateral: 3 equal sides and three 60° angles. Isosceles: 2 equal sides, and the angles opposite those sides are equal.

### 📌 Sum of lengths of two sides The sum of the lengths of any two sides of a triangle is strictly greater than the length of the third side.

### 📌 Right-angled triangle & Pythagoras property In a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.

Key Formulas Mind Map

• Angle Sum Property: `A + B + C = 180^\circ` - Interior angles of a triangle sum to 180 degrees....
• Pythagoras Theorem: `a^2 + b^2 = c^2` - Sum of squares of legs equals square of hypotenuse c in right triangle....

Revision Checklist

1. Review the subtopic guides and outline notes.
2. Practice writing the key formulas from memory.
3. Solve at least 3 worked examples and check your steps.
4. Take a timed practice quiz to verify your speed.