Chapter 9: Boxes and Sketches

Math • Class 5

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Chapter Analysis

Beginner8 pages • English

Quick Summary

The chapter 'Boxes and Sketches' is designed to help students understand the visualisation of 3-dimensional shapes and their representation in 2 dimensions. Key concepts include using nets to create boxes, understanding layout plans, and drawing 3D shapes in perspective to convey depth. The chapter also introduces practical exercises for constructing boxes from nets and drawing objects from different perspectives.

Key Topics

  • 3D visualization of shapes
  • Nets and layouts for creating boxes
  • Perspective drawing and depth representation
  • Constructing open and closed boxes
  • Interpreting floor maps

Learning Objectives

  • Understand how 3D shapes can be represented in 2D through nets.
  • Learn to differentiate between different views and perspectives of 3D objects.
  • Develop spatial reasoning through constructing shapes from various nets.
  • Recognize the importance of perspective in architectural plans and drawings.
  • Engage in activities that encourage hands-on manipulation of geometric shapes.

Questions in Chapter

How many faces does a cube have?

Answer: A cube has 6 faces.

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Will both these shapes fold into a cube? Draw at least one more shape which can fold into a cube.

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What will be the area of each face of the cube?

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Find out which of the other 8 shapes can be folded to make an open box.

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Draw more shapes which will not fold to make an open box.

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Match the shape on the left with a box into which it will fold.

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Which is the front side of her house? How many windows are there on the front side?

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Why do the other three deep drawings not match the floor map? Discuss.

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Make drawings to show how this bridge will look from different perspectives.

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Additional Practice Questions

Create a net for a triangular prism. Explain each step of constructing the net.

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Answer: To create a net for a triangular prism, draw two identical triangles for the bases. Then, draw three rectangles that connect corresponding sides of the triangles. Ensure the length of each rectangle matches the corresponding triangle's side.

Given a layout plan of a building, illustrate how you would represent it in a deep drawing.

hard

Answer: First, understand the dimensions from the layout. Draw the front view with proper scaling for height and width, then add lines to suggest depth. Add side and top views if possible to give a complete 3D perspective.

What characteristics distinguish a net that can or cannot form a cube? Provide examples.

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Answer: Nets that form a cube have six connected squares where among them, no more than four are in a straight line. For example, a T-shaped net can form a cube, whereas a straight line of six squares cannot.

Imagine a box that cannot close fully because of misplaced flaps. How would you redesign the net to fix this issue?

easy

Answer: Review and adjust the net by ensuring all outer edges are properly aligned. Flaps should attach seamlessly along edges without overlap beyond their adjacent faces. Redesign to include all necessary flaps for closure.

Describe how perspective drawing differs from orthographic projections. Provide sketches to illustrate.

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Answer: Perspective drawing represents depth and converges at vanishing points, showing objects as they appear to the eye. Orthographic projections show different views separately with true dimensions without perspective distortion.