Measurement of Area
The space covered by a plane surface is called area. Its SI unit is square meter (m2). If the surface area of objects is regular, its surface area is calculated by simple arithmetic.
Area of rectangle = Length Ã—Breadth
i.e. A = lÃ—b
Area of a triangle = (Base Ã— Height)/2
i.e. A = (bÃ—h)/2
Area of a circle = Ï€ (radius)2
The surface area of any irregular body is determined by a graph paper method. The SI unit of area is square meter (m2).
Measurement of volume
The space covered by a plane surface is called area. Its SI unit is square meter (m3). For the regular shaped body, the volume of a solid is determined by simple arithmetic.
Volume of a rectangular parallelepiped body = lengthÃ—breadthÃ—height
i.e. V = l Ã— b Ã— h
Volume of a cylinder = Ï€ (radius)2 Ã— length
i.e. V = Ï€r2l
Volume of a sphere = 4Ï€(radius)3/3
i.e. V = 4Ï€r3/3 = Ï€d3/6
Example: Express the following in power of 10.
1,000,000,000 = 1Ã—109 = 109
0.000,000,0062 = 6.2Ã—109
2Ã—106Ã—10-3 = 2Ã—106 + (-3) = 5Ã—103