## Friday, 30 November 2012

### BASIC MENSURATION FORMULA

UNIT-
You should be familiar with the following units:
1.              Length: mm, cm, m, km
2.             Area: mm2, cm2, m2, ha, km2
3.             Volume: mm3, cm3, m3
4.             Capacity: ml, cl, l
5.             Mass: g, kg
•        To convert from smaller to larger units we divide by the conversion factor.
•       To convert from larger to smaller units we multiply by the  conversion factor
LENGTH-

The perimeter of a figure is the measurement of the distance
around its boundary.
For a polygon the perimeter is the sum of the lengths of all
sides

UNIT-METER
AREA-
The area of a figure is the amount of surface within its
boundaries.
You should be able to use these formulae for area

Rectangles- Area = (length * width)

Triangles-Area = 1/2 (base * height)
Parallelograms-Area = base * height
Trapezia-Area = 1/2 (a + b) * h

VOLUME-
The volume of a solid is the amount of space it occupies.You should be able to use these formulae for volume:Solids of uniform cross-section--

Volume of uniform solid = area of end * height

Pyramids and cones= 1/3 (area of base * height)
Volume of a sphere = 4/3(pi)r3

SURFACE AREA

Solids with plane faces
The surface area of a three dimensional figure with plane facesis the sum of the areas of the faces.
To assist in your calculations, you can draw a net of the solid,
correctly labelling the dimensions.
Solids with curved surfaces
You should be able to use these formulae for surface area: