Circumference of circle
2 πr
Area of a circle
πr.sq
Area of a square
L.sq
Perimeter of a square
4L
Perimeter of a rectangle
2L + 2b or 2(L+b)
Area of a triangle
(h x base)/2
Perimeter of a triangle
a+b+c
∈
Belongs to
N
Natural numbers
W
Whole numbers
Z
Integers
⊂
Proper subset
⊆
Subset (proper or improper we don’t know)
⊄
Not a subset
Equal set definition
They have the same elements
Equivalent sets
They have the same number of element
Formula for the number of subsets
2^n when n is the number of elements of the set
Square root of 121
11
Square root of 144
12
Square root of 169
13
Square root of 225
15
Square root of 289
17
Square root of 361
19
Square root of 529
23