Need To Know Equations Flashcards
Percentage change
%change= actual change/original amount *100
Compound interest after multiple changes
Original*d^n
Sum of interior angles =
(Number of sides - 2)*180
Sum of exterior angles =
360
For regular polygons, each exterior angle =
360/number of sides
Pythagoras’ theorem
A^+B^2=C^2
Gradient
Change in y/Change in x
Midpoints
(X1 + X2 /2 , Y1+Y2/2)
Distance between points
(Change in x, change in y)
Quadratic graphs
y=ax^2+bx+c
Cubic graphs
y=ax^3
Reciprical graphs
y=a/x
Circle graphs
x^2+y^2=r^2
Area of triangle
1/2baseperpendicular height
Area of a parallelogram
Base*perpendicular height
Area of a trapezium
a+b/2*h
Volume of pyramid
1/3abh
Volume of cone
1/3🥧r^2*h
Volume of a prism
Cross sectional area * height
Volume of a sphere
4/3🥧r^3
Volume of hemisphere
2/3🥧r^3
Area of a kite
1/2LW
Area of a sector
Angle of sector/360 * area of circle
Surface area of a cylinder
2🥧r^2 + 2🥧rh
Surface area of a sphere
4🥧r^2
Surface area of a cone
🥧r^2 + 🥧rl
Frequency density
= frequency/class width
Sine rule for lengths
a/sin(A) =b/sin(B) =c/sin(C)
Sine rule for angles
sin(A)/a =sin(B)/b =sin(C)/c
Cosine rule for lengths
a2 = b2+c2 - 2(b)(c) cos (A)
Cosine rule for angles
Cos A = b2+c2-a2 / 2(b)(c)
