Area Formulas
Area of a Triangle (if given the height)
A = (1/2)bh
Area of a Parallelogram
A = bh
Density Formula
D = m/v
Sum of the Exterior Angles of a Polygon
360°
Pythagorean Theorem
a2 + b2 = c2
Area of a Circle
A = π r2
Area of a Rectangle
A = lw
Slope Formula
m = (y2 - y1)/(x2 - x1)
Each (or one) of the Exterior Angles of a Regular Polygon
∠ = 360° / n
What is another name for a 45-45-90 Triangle?
Isosceles Triangle
Area of a Square
A = s2
Area of a Trapezoid
A = (1/2)h(b1+b2)
Midpoint Formula
( (x1 + x2)/2 , (y1 + y2)/2 )
The Apothem is what to a Regular Polygon's Central Angle:
Angle Bisector
45-45-90 Triangle
Formula for H
H = L √ 2
Area of a Regular Polygon
A = (1/2)aP
Area of a Rhombus
A = (1/2)(d1d2)
Equation of a Circle
(x-h)2 + (y-k)2 = r2
Sum of the Interior Angles of a Polygon
Sum = (n-2)180°
30-60-90 Triangle
Formula for H
AND
Formula for L
H = 2s
L = s √ 3
Area of a Triangle (if given two sides and the included angle)
A = 1/2 ab sin(C°)
Area of a Sector
A = π r2 (m°/360°)
Three Different Forms of Equation of a Line
y = mx + b
Ax + By = C
y - y1 = m(x - x1)
Each (or one) of the Interior Angles of a Regular Polygon
∠ = (n-2)180° / n
Distance Formula
d = √(x2-x1)2 + (y2-y1)2