NCERT Class 9 Maths Lab Manual - Verify that the Sum of the Angles of a Triangle is 180° OBJECTIVE To verify that the sum of the angles of a triangle is 180°. Materials Required Cardboard sheet White chart paper Geometry box Scissors Adhesive Drawing sheet Tracing paper Prerequisite Knowledge Knowledge of straight angle Concept of triangle … [Read more...] about NCERT Class 9 Maths Lab Manual – Verify that the Sum of the Angles of a Triangle is 180°