Formulae and Rules Flashcards
Angles in Parallel line rules for:
Corresponding angles
Vertically opposite
Alternate angles
Co-interior angles
Angles on a straight line
Corresponding angles are equal
Vertically opposite angles are equal
Alternate angles (Z) are equal
Angles on a straight line add to 180 deg
Co- interior angles add to 180 deg (C)
Area of a circle
Perimeter of a circle
Volume of a cylinder
SA of a cylinder
area of a circle = πr^2
perimeter of a circle =πD or 2πr
Volume of a cylinder = πr^2h
SA cylinder - work out area of circles and rectangle then add tg
REMEMBER - be careful when a semicircle or semicylinder is involved, divide by 2 whenever necessary.
Volume of a prism:
cross sectional area x length
Area of parrallelogram
base x height
Area of trapezium
1/2(a + b)h
where a and b are the top and bottom lines:
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How do we work out the gradient of a line from a graph?
rise/run
How do we work out the gradient of a line from its coordinates
m = (y2 −y1 )/(x2 −x1 ) = Δy/Δx
How do we work out the midpoint of 2 coordinates
(X1 + X2)/2 to get x
(Y1 + Y2)/2 to get y
on a histogram which axis does the factor eg height and the frequency density go?
Factor on the x axis
Frequency density on the y axis
so the area of each bar = frequency (number of wtv)
because frequency density = frequency/class width
Quadratic formula:
x = [-b ± √(b2 - 4ac)]/2a.
The area of any triangle =
1/2abSinC
C = angle
a and b are lengths
The Sine rule is to work out?
The angle and lengths of triangle that has opposites.
We use cosine rule when no opposites and non right angled triangle - 2 LENGTHS WITH ANGLE IN BETWEEN.
Cosine length rule:
a^2 = b^2 + c^2 - 2bcCosA
Cosine angle rule:
CosA = (b^2 + c^2 - a^2)/2bc
When do we use the cosine angle rule?
When we know all three of the lengths and we want to work out an angle.
