Parallel and Intersecting Lines

About this chapter

Parallel and Intersecting Lines is Chapter 5 of Class 7 Ganita Prakash Part 1. It builds the language of lines on a plane surface and tests it through angles. The chapter opens with paper-folding and moves to intersecting lines that form four angles, with linear pairs adding to 180 degrees and vertically opposite angles equal. Perpendicular lines are introduced as a special intersection where all four angles are 90 degrees. Parallel lines are defined as a pair on the same plane that never meet, illustrated by piano keys, bench rails and floor tiles. The chapter then introduces a transversal cutting two lines, naming the eight angles formed and the four corresponding-angle pairs. Equality of corresponding angles is shown as both necessary and sufficient for parallelism. Alternate angles and co-interior angles are derived from corresponding-angle facts, and notations (single and double arrows, the right-angle square) are formalised. For CTET Paper 2 Mathematics, this chapter is tested through vertically opposite angles, linear pairs, perpendicular and parallel definitions, transversal angle calculations and parallel-line reasoning. The four tests below — Practice 15 Q, Quiz 15 Q, Hard 15 Q, Mastery 30 Q — cover all eight sections at the right depth.