# NCERT Class 9 MathematicsHerons Formula (Mensuration) Board Sample Problems

Doorsteptutor material for CBSE is prepared by world's top subject experts: fully solved questions with step-by-step explanation- practice your way to success.

**Mensuration**

It is branch of mathematics which is concerned about the measurement of length, area and Volume of plane and Solid figure

**Perimeter**

The perimeter of plane figure is defined as the length of the boundary

It units is same as that of length i.e. m, cm, km

1 Meter | 10 Decimeter | 100 centimeter |

1 Decimeter | 10 centimeter | 100 millimeter |

1 Km | 10 Hectometer | 100 Decameter |

1 Decameter | 10 meter | 1000 centimeter |

Area

The area of the plane figure is the surface enclosed by its boundary

It unit is square of length unit. i.e.

1 square Meter | 100 square Decimeter | 10000 square centimeter |

1 square Decimeter | 100 square centimeter | 10000 square millimeter |

1 Hectare | 100 square Decameter | 10000 square meter |

1 square myraimeter | 100 square kilometer | square meter |

**Perimeter and Area of different figure**

N | Shape | Perimeter/height | Area |

1 | Right angle triangle Base =b, Height =h Hypotenuse=d | P Height =h | |

2 | Isosceles right angled triangle Equal side =a | Height=a | |

3 | Any triangle of sides a ,b, c | Where This is called Heron’s formula (sometimes called Hero’s formula) is named after Hero of Alexandria | |

4 | Square Side =a | P=4a | |

5 | Rectangle of Length and breath L and B respectively | P=2L+2B | |

6 | Parallelograms Two sides are given as a and b | P=2a+2b | When the diagonal is also given, say d Then Where |

7 | Rhombus Diagonal and are given | ||

8 | Quadrilateral a) All the sides are b) Both the diagonal are perpendicular to each other c) When a diagonal and perpendicular to diagonal are given | a) P | a) Where b) where and are the diagonal c) where d is diagonal and and are perpendicular to that |