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.
When do we use the cosine length rule?
2 lengths with an angle in between.
