# Ex.14.3 Q4 Symmetry - NCERT Maths Class 7

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## Question

Fill in the blanks – Shape; Centre of Rotation; Order of Rotation; Angle of Rotation; for each of the figures respectively.

Shape |
Centre of Rotation |
Order of Rotation |
Angle of Rotation |

Square | |||

Rectangle | |||

Rhombus | |||

Equilateral Triangle | |||

Regular Hexagon | |||

Circle | |||

Semi-circle |

## Text Solution

**What is known?**

Shapes

**What is unknown?**

Centre of rotation, order of rotation and angle of rotation.

**Reasoning:**

**Centre of rotation:** In case of polygon centre of rotation is intersecting point of diagonals and in case of circle centre of rotation is centre of the circle.

**Order of rotation: **In case of regular polygon order of rotation is always equals to the number of sides and in case of circle order of rotation is infinite.

**Angle of rotation:** In case of regular polygon angle of rotation is always equals to the measurement of one angle and in case of circle angle of rotation is at every point.

**Steps:**

Shape |
Centre of Rotation |
Order of Rotation |
Angle of Rotation |

Square | Intersecting points of diagonals | \(4\) | 90° |

Rectangle | Intersecting points of diagonals | \(2\) | \(180^\circ\) |

Rhombus | Intersecting points of diagonals | \(2\) | \(180^\circ\) |

Equilateral Triangle | Intersecting points of diagonals | \(3\) | \(120^\circ\) |

Regular Hexagon | Intersecting points of diagonals | \(6\) | \(60^\circ\) |

Circle | Mid- point of diameter | Infinite | At every point |

Semi-circle | Mid- point of diameter | \(1\) | \(360^\circ\) |