Quantitative Aptitude Mensuration Study Material
In mensuration we proceed to determine the lengths of lines, areas of plane surface* and volumes of solids. First of all we shall discuss the areas of two dimensional figures (2-D) like rectangle, square, triangle, circle, parallelogram, rhombus and trapezium and their perimeters. We shall also study some shoit-cut methods to solve such problems. Let us begin this topic by having a sincere look at the basic definition. Rectilinear Figures : A figure made up of line segments is known as a rectilinear figure. The line segments forming the figure are called the sides of the figure. A rectilinear figure having no free ends is said to be a closed figure. A rectilinear figure is said to be simple if no two sides of it intersect except at a common appoint. Therefore, a rectangle, a square, a triangle, a quadrilateral, a parallelogram, a rhombus and a trapezium are all simple closed rectilinear figures or two dimensional figures. Region: The part of the plane enclosed by a simple closed figure is called a region. . - • Area : The magnitude of a plane region enclosed by a simple closed figure is called its area. Standard Unit of Area : A square centimetre is the area of the region formed by a square of side 1 cm. A square centimetre (written as cm2 or sq. cm.) is a standard unit of area. Other standard units of area and their inter- relationships are listed below for ready reference: 1 square centimetre (cm2) = 1cm x 1cm = 10mm x 10mm = 100 sq. mm 1 square decimetre (dm2) = 1 dm x 1 dm = 10 cm x 10cm = 100 sq.cm. 1 square metre (m2) = lmx lm = 10dmx 10dm = 100sq.(dm2) =100cm x 100cm = 10,000(cm2) 1 acrc= 100(m2) 1 hectare= 100 acres 1 hectares 10,000(m2) 100 hectares = 1km2 Perimeter: Perimeter of a plane figure is the measure of the length of its boundary. Unit of Perimeter: The unit of perimeter is same as the unit of length. i.e centimetre (cm), metre (m), kilometre (km) etc. The inter-relationshjp between different units of measurement of length are listedd below for ready reference: 1 centimetre(cm)=10 millimeters (mm) 1 decimetre (dm)= 10 centimeters 1 metre(m)= 10 decimeters = 100 centimetres =1000 millimeters 1 decametre (dam)=10 meters= 1000 centimetres 1 hectometre (hm) = 10 decametres = 100 metres 1 kilometre (km) = 1000 metres = 100 decametres = 10 hectometres ' 1 myriametre= 10 kilometres. In mensuration it is very important to know and understand the basic formulae. So, we shall I first see the basic formulae:
No comments:
Post a Comment