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Formulas for Geometry
Figure
Area
Perimeter
Triangle
Square
Rectangle
Parallelogram
Trapezoid
Circle
Prism
Pyramid
Rectangular Solid
Cube
Cylinder
A = 12 bh
P = s1 + s 2 + s3
P = 4s
P = 2l + 2 w
Add the sides
Add the sides
c = πd = 2πr
A=s
A = lw
A = bh
A = 12 h(b1 + b2 )
2
A = πr 2
Surface Area
(Right only, if applicable)
Volume
Cone
S = πr 2 + πr r 2 + h 2
V = Bh
V = 13 Bh
V = lwh
V = s3
V = πr 2 h
V = 13 πr 2 h
Sphere
S = 4πr 2
V = 43 πr 3
Add the rectangles
Add the triangles
S = 2lw + 2lh + 2 wh
S = 6s 2
S = 2πr 2 + 2πrh
Sum of the measures of the interior angles of an n-sided polygon
S = (n − 2)180 o
Perimeter of a polygon
P = s1 + s 2 + s3 + L + s n
where the si are the lengths of the sides and n is the number of sides
Pythagorean Theorem
c2 = a 2 + b2
Euler’s Polyhedron Formula
Number of vertices – number of edges + number of faces = 2
Sides
7
8
9
10
12
20
Name
Heptagon
Octagon
Nonagon
Decagon
Dodecagon
Icosagon