Joining two congruent copies of any triangle along a shared edge forms a parallelogram. Since identical parallelograms tile the plane continuously, splitting each parallelogram into its two constituent triangles tiles the entire plane.
Class 9 Ganita Manjari Part 2 chapter 12 Quadrilaterals solutions
Class 9 New Ganita Manjari Part 2 Book Solutions
Rotate a copy of the triangle by 180° and join it with the original along an equal side to form a parallelogram. As established, identical parallelograms can tile the plane seamlessly without overlaps or gaps. By decomposing every parallelogram in that grid into the two original congruent triangles along their diagonals, we obtain a complete tiling of the plane using copies of the triangle.
For more NCERT Solutions of Class 9 Maths Ganita Manjari Part 2 Chapter 12 Quadrilaterals Question Answer (2026-27)
https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-12/