USING FORMULAS IN GEOMETRY
Geometry H2 (Holt 1-5) K. Santos
Area
Area (A) is the number of nonoverlapping square units of a given size that exactly cover the figure
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Area of Rectangle
Area = product of its base and height
b
A= bh h
3 ft
5 ft
Area of a Square
Area = product of its base and height
A= bh
6 in
Area of a Triangle
Area = one half of the product of its base and height
A= bh or A = Base perpendicular to height
h h h
b b b
If b = 4” and h = 6”
Example—finding a side
The area of a triangle is 24 and its height is 3 cm. Find the length of its corresponding base.
A =
Perimeter
Perimeter (P) of a plane figure is the sum of the side lengths of the figure
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Perimeter Formulas
Rectangle: l
P = 2l + 2w w
Square:
P = 4s s
Triangle:
P = a + b + c
a b
c
Circle Formulas
8 ft
Area:
Circumference: