# NCERT Class 8 Mathematics Chapter 11 Mensuration CBSE Board Sample Problems

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## Mensuration

Sr. no | Term | Description |

1. | Mensuration | It is branch of mathematics which is concerned about the measurement of length, area and Volume of plane and solid figure. |

2. | 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 |

3. | Area | The area of the plane figure is the surface enclosed by its boundary It unit is square of length unit. i.e. |

### Shapes Where Area and Perimeter Are Known

Shapes | perimeter | Area |

Rectangle | P=2(L+B) L and B are Length and Breadth of the rectangle | |

Square | P=4a A is side of the square | |

Triangle | P=sum of sides | |

Parallelogram | P=2(sum of adjacent sides) | |

Circle | r is the radius of the circle | |

Trapezium | P=sum of length of all the sides | Half the product of the sum of the lengths of parallel sides and the perpendicular distance between them gives the area of trapezium |

General Quadrilaterals | P=sum of length of all the sides | |

Rhombus | P=4a | Where d |

**Important Terms to remember in case of solid figures**

Surface Area | Surface Area of a solid is the sum of the areas of its faces |

Lateral Surface Area | The faces excluding the top and bottom make the later Surface Area of the solid |

Volume | Amount of space occupied by a three dimensional object (solid figure) is called its volume. We use square units to find the area of a two dimensional region. In case of volume we will use cubic unit to find the volume of a solid, as cube is the most convenient solid shape (just as square is the most convenient shape to measure area of a region) Volume is sometimes refer s capacity also |

### Surface Area and Volume of Cube and Cuboid

Type | Measurement |

Surface area of cuboid of length L, Breadth B and Height H | |

Lateral Surface Area of the cuboids | |

Diagonal of the cuboids | |

Volume of a cuboids | LBH |

Length of all 12 edges of the cuboids | |

Surface Area of cube of side L | |

Lateral Surface Area of the cube | |

Diagonal of the cube | |

Volume of a cube |

**Surface Area and volume of Right circular cylinder**

Radius | The radius (r) of the circular base is called the radius of the cylinder |

Height | The length of the axis of the cylinder is called the height (h) of the cylinder |

Lateral surface | The curved surface joining the two base of a right circular cylinder is called lateral surface. |

Type | Measurement |

Curved or lateral Surface Area of cylinder | |

Total Surface Area of cylinder | |

Volume of cylinder |