Formulas Cheat Sheet
Perimeter – The distance around a polygon.
For any polygon, just add all of the sides together to find the perimeter.
Circumference – The distance around a circle.
C=   d
or C = 2    r
Area – The amount of space contained in a two dimensional shape. ALWAYS given in
units2. (Ex. in2, cm2, etc…)
Circle:
A =   r2
---------------------------------------------------------------------------------------------------------------------------Rectangle/Square: A = b  h
---------------------------------------------------------------------------------------------------------------------------Trapezoid:
A = (b1 + b2)  h  2
---------------------------------------------------------------------------------------------------------------------------Triangle:
A = b h  2
---------------------------------------------------------------------------------------------------------------------------Pythagorean Theorem – Use to find missing lengths of right triangles. Always need to find
a square root in a Pythagorean Theorem problem.
Solve for side C
Solve for side A
Solve for side B
2
2
2
2
2
2
C =A +B
A =C –B
B2 = C2 – A2
---------------------------------------------------------------------------------------------------------------------------Surface Area – The sum of all of the areas of the faces from a three dimensional shape.
ALWAYS given in units2. (Ex. in2, cm2, etc…)
Prism:
SA = Sum of the areas of the polygon faces.
---------------------------------------------------------------------------------------------------------------------------Cylinder:
SA = (2    r2) + (2    r  h)
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Volume – The amount of space contained inside of a three dimensional object. ALWAYS
given in units3. (Ex. in3, cm3, etc…)
Cylinder:
V = (area of base)  height
base is a circle
---------------------------------------------------------------------------------------------------------------------------Rectangular Prism: V = (area of base)  height
base is a rectangle
---------------------------------------------------------------------------------------------------------------------------Triangular Prism:
V = (area of base)  height
base is a triangle
---------------------------------------------------------------------------------------------------------------------------Cone:
V = (area of base)  height  3
base is a circle
---------------------------------------------------------------------------------------------------------------------------Pyramid:
V = (area of base)  height  3
base can be any polygon
---------------------------------------------------------------------------------------------------------------------------Sphere
V = (r3    4)  3
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