Complete this table for polyhedra. Number of vertices Number of faces Number of edges Shape A 10 16 Shape B 10 12 Shape C 11 6

The relation among the vertices, faces, and edges by the Euler's formula is- V + F - E = 2 , where V is the number of vertices, F is the number of faces, and E is the number of edges. By putting the values for shape A- 10 + F - 16 = 2 ⇒ F = 2 + 6 = 8 For shape B- V + 10 - 12 = 2 ⇒ V = 2 + 2 = 4 For shape C- 11 + 6 - E = 2 ⇒ E = 17 - 2 = 15 Thus, the completed table is- Number of vertices Number of faces Number of edges Shape A 10 8 16 Shape B 4 10 12 Shape C 11 6 15

E M B I B E

Cambridge Lower Secondary Maths Stage 8 : Workbook>Chapter 2 - 2D and 3D Shapes>Exercise 2

EASY

Lower Secondary Stage 8

IMPORTANT

Earn 100

A regular decagon has rotational symmetry of order $12$ .

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Important Questions on 2D and 3D Shapes

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Maths Stage 8 : Workbook>Chapter 2 - 2D and 3D Shapes>Exercise 2

Decide if the following statements could be true or cannot be true. Give reasons for your answer.

The polygon has no lines of symmetry.

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Maths Stage 8 : Workbook>Chapter 2 - 2D and 3D Shapes>Exercise 2

Decide if the following statements could be true or cannot be true. Give reasons for your answer.

The shape has rotational symmetry of order $7$ and has $7$ lines of symmetry.

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Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Maths Stage 8 : Workbook>Chapter 2 - 2D and 3D Shapes>Exercise 3

Explain how Euler's formula is illustrated in the following 3D shape.

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MEDIUM

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Maths Stage 8 : Workbook>Chapter 2 - 2D and 3D Shapes>Exercise 3

Explain how Euler's formula is illustrated in the following 3D shape.

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MEDIUM

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Maths Stage 8 : Workbook>Chapter 2 - 2D and 3D Shapes>Exercise 3

Explain how Euler's formula is illustrated in the following 3D shape.

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MEDIUM

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Maths Stage 8 : Workbook>Chapter 2 - 2D and 3D Shapes>Exercise 3

Complete this table for polyhedra.

	Number of vertices	Number of faces	Number of edges
Shape A	10		16
Shape B		10	12
Shape C	11	6

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Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Maths Stage 8 : Workbook>Chapter 2 - 2D and 3D Shapes>Exercise 3

Mae says she has made a polyhedron with $13$ faces, $4$ vertices, and $11$ edges. Amber tells her that she has the number of faces, vertices, and edges mixed up.

The numbers are correct, but the names are mixed up. What are the different possible correct combination?

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Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Maths Stage 8 : Workbook>Chapter 2 - 2D and 3D Shapes>Exercise 4

Find the circumference of a circle with diameter. Round your answer to $1$ decimal place.

$8 cm$