Monday, 25 February 2013

MATH SHAPE FORMULA

Shapes
Formula
Rectangle:
Area = Length X Width
A = lw

Perimeter = 2 X Lengths + 2 X Widths
P = 2l + 2w
Parallelogram
Area = Base X Height
a = bh
TriangleArea = 1/2 of the base X the height
a = 1/2 bh
Perimeter = a + b + c
(add the length of the three sides)

Trapezoid

Perimeter = area + b1 + b2 + c
P = a + b1 + b2 + c
Circle Try the Online tool.
The distance around the circle is a circumference. The distance across the circle is the diameter (d). The radius (r) is the distance from the center to a point on the circle. (Pi = 3.14) More about circles.
d = 2r
c = pd = 2 pr
A = pr2
(p=3.14)
Rectangular Solid
Volume = Length X Width X Height
V = lwh
Surface = 2lw + 2lh + 2wh
Prisms
Volume = Base X Height
v=bh
Surface = 2b + Ph (b is the area of the base P is the perimeter of the base)
Cylinder
Volume = pr2 x height
V = pr2 h
Surface = 2p radius x height
S = 2prh + 2pr2
Pyramid
V = 1/3 bh
b is the area of the base
Surface Area: Add the area of the base to the sum of the areas of all of the triangular faces. The areas of the triangular faces will have different formulas for different shaped bases.
ConesVolume = 1/3 pr2 x heightV= 1/3 pr2h 
Surface = pr2 + prsS = pr2 + prs 
=
pr2 + pr
SphereVolume = 4/3 pr3V = 4/3 pr3
Surface = 4pr2S = 4pr2

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