Chapter 1 — Shapes Around Us

It is about shapes around us — the chapter covers 3D solids (prisms, pyramids, cube, cuboid), angles (right, acute, obtuse), and 2D shapes (triangles, rectangles, circles). Activities involve building models, folding nets, and exploring properties of shapes.

A net is the flat, unfolded version of a 3D shape. Diksha folds open a box to show its net. The chapter provides nets at the back of the book so students can fold them to make prisms and pyramids.

A square pyramid has 5 faces, 8 edges, and 5 corners. The chapter asks students to fill in a table for different shapes and discover the F + V − E pattern.

Prisms have rectangular faces connecting two identical parallel bases, while pyramids have triangular faces that all meet at a single point (apex). The chapter asks students to discuss this difference after building both types.

Fold a piece of paper in half and then fold it in half again — the corner formed is a right angle. The chapter calls this a right-angle checker and students use it to test angles on books, windows, and other objects.

Acute angles are smaller than a right angle and obtuse angles are larger than a right angle. The chapter asks students to identify both types in classroom objects and in alphabet letters.

The radius is the distance from the centre of a circle to its edge. The diameter is a line passing through the centre from one side to the other, and it equals twice the radius. Students discover this by folding circular paper and measuring the creases.

When you push one side of a triangle made from straws, its shape does not change — this is called rigidity. A rectangle, by contrast, deforms into a different angle shape when pushed, so the triangle is the strongest and most rigid polygon.

The chapter mentions India Gate, Qutub Minar, Safdarjung Tomb, Akshardham, the National Museum, Jantar Mantar, and Sansad Bhawan. Diksha visits them and then tries to build a model of India Gate using wooden blocks. The Qutub Minar is noted as a World Heritage site with 5 storeys and 379 stairs.

Squiggly the spider makes triangular and rectangular webs. Students count how many triangles or rectangles are in the web and trace a path for the spider that covers every wall exactly once — this is a fun shape and path-tracing puzzle.

Students sort 3D shapes by the number of flat faces (1, 2, 4, 5, 6, or 8), by straight vs curved edges, and by the types of faces (triangular, rectangular, or both). Venn diagrams using overlapping circles are used for shapes that fall into two categories.

Students learn to draw a circle using a compass by fixing the centre point and rotating the pencil arm at a constant radius. The chapter also shows a step-by-step design using multiple circles and asks students to mark the centre, radius, and diameter on the final circular design.