Area and Perimeters of Square
Perimeter = 4s
Area = s^2
Area and Perimeter of Triangle
Perimeter = a + b + c
Area = 1/2(bh) OR bh/2
Area and Perimeter of Rectangle
Perimeter = 2L + 2W
Area = L x W
Area and Circumference of Circles
Circumference = πd
(pi = 3.14) d = r x 2
Area = πr^2
r = 2 divided by d
Area and Perimeter of Trapezoid
Perimeter = a + b + c + d
Area = a+b/2 x h
Area and Perimeter of Parallelogram
Perimeter = 2(a+b)
Area = bh
Area and Perimeter of Rhombus
Perimeter = 4s
Area = 1/2 d1 d2 or bh
Volume and Surface Area of Cube
Surface Area = 6(s^2)
Volume = S^3
Volume and Surface Area of Rectangular Prism
Surface area = 2lw + 2hw + 2lh
Volume = lwh
Volume and Surface area of Sphere
Surface area = 4 πr^2
Volume = 4/3 πr^3
Volume and Surface area of Cylinder
Surface Area = 2πrh + 2πr^2
Volume = πr^2h
Radius & Diameter
Radius (r)
The distance from the center of a circle to any point on its edge.
Formula:
r = d/2
Diameter (d)
The distance across the circle through its center (twice the radius).
Formula:
d = 2 x r
Quick Tip:
Diameter = 2 × Radius
Radius = Diameter ÷ 2
Pythagorean Theorem
a^2 + b^2 = c^2
Volume and Surface Area of Cone
Volume = 1/3 = πr^2h
Surface Area = πr(r+1)
Pythagorean Triples
3,4,5
5,12,13
20,99,101
6,8,10
7, 24, 25
20, 21, 29
48, 55, 73
7, 24, 25
8, 15, 17
17, 144, 145
Isosceles Triangle
If any two sides are equal, it’s isosceles.
Example: sides 5, 5, and 8 → isosceles.
Right Triangle
A triangle with one 90° angle.
Acute Triangle
A triangle where all angles are less than 90°.
• Using sides: If a^2 + b^2 > c^2 → all angles are acute (for sides in order a ≤ b ≤ c). • Using angles: If all three angles are < 90°, it’s acute.
Equiangular Triangle
A triangle where all three angles are equal
Obtuse Angle
above 90 degrees
