# NCERT Class 9 Maths Formula CBSE Board Sample Problems Part 11 (For CBSE, ICSE, IAS, NET, NRA 2022)

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## 11. Heron Formula

 S. 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 (a) The perimeter of plane figure is defined as the length of the boundary(b) Its units are same as that of length i.e.. . , m, cm, km 3 Area (a) The area of the plane figure is the surface enclosed by its boundary(b) Its unit is square of length unit. i.e.. . ,

Unit Conversion

 1 Meter 10 Decimeter 100 centimeter 1 Decimeter 10 centimeter 100 millimeter 1 Km 10 Hectometer 100 Decameter 1 Decameter 10 meter 1000 centimeter 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 triangleBase = b, Height = hHypotenuse = d 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 5 Rectangle of Length and breadth L and B respectively A = LX B 6 Parallelograms Two sides are given as a and b A = Base X heightWhen the diagonal is also given, say dThenW here 7 Rhombus Diagonal d1 and d2 are given 8 Quadrilateral(a) All the sides are given a, b, c, d(b) Both the diagonal are perpendicular to each other(c) When a diagonal and perpendicular to diagonal are given where d is diagonal and and are perpendicular to that (a) (a) Where (b) Where and are the diagonal(c)

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