maths Flashcards
what is the formula for the area of a trapezium
area of a trapezium= (sum of two widths/2) x height
what is the formula for the area of a triangle
area of a triangle= length x width / 2
what is the formula for the area of a circle
area of a circle= pi x radius^2
what is the formula for calculating the mean of a set of numbers
mean= sum of all numbers / amount of numbers
what is the formula for the circumference of a circle
circumference of a circle= pi x diameter
what is the formula for the sine rule
a/sin(a)=b/sin(b)=c/sin(c)
what is the quadratic formula
x= (-b+- square root (b^2 - 4ac)) / 2a
what is the formula for the cosine rule
a^2= b^2 + c^2 - (2ab x cos(a))
what is the formula for the area of a sector
area of a sector= (theta/360) x pi x radius^2
what is the formula for the perimeter of a sector
perimeter of sector= ((theta/360) x pi x diameter) + (2 x radius)
what are the 4 criteria for congruence in triangles
SAS (Side angle side), SSS (side side side), AAS (angle angle side), RAS (right-angle side angle)
what is the Pythagorean theorem
a^2 + b^2 = c^2
what is the formula needed when plotting a histogram
frequency= class width x frequency density
what is the circle theorem for a triangle where one line is a diameter and all points are on the circumference
angle inside a semicircle = 90 degrees
what is the circle theorem for the angles inside a 4 sided shape inside a circle where all points touch circumference called
opposite angles in a cyclic quadrilateral =180 degrees
what is the circle theorem for where a radius and tangent meet
when a radius and tangent meet, the angle created is 90 degrees
what is the circle theorem about two meeting tangents
two tangents that meet at a point are the same length
what is the circle theorem about an angle at the origin and an angle at the circumference
the angel at the origin is double the angle at the circumference
what is the circle theorem about angles in the same segment and standing on the same chord
angles in the same segment and standing on the same chord are equal.
what is the formula for inverse proportion
y=k/x
what is the formula for direct proportion
y = kx
what is the square root of 225
15 or -15
