What’s the relationship between the slopes of perpendicular lines
They are opposite reciprocals
Opposite = change the sign
Reciprocal = put a 1 over it
(m1=3 and m2=-1/3
Circumference
c=2piR
c=piD
How do you find the distance between 2 points on the XY plane
Pythagorean theorem on rise/run triangle
Area of trapezoid
average of bases (sides) * height
Pythagorean triplets
3,4,5
5,12,13
8,15,17
(And their multiples)
Length of the diagonal between opposite vertices of a cube with edge-length s
(diagonal)^2 = s^2 + s^2 + s^2 = 3s^2
(diagonal) = s(sqrt3)
Volume of cube
v = s^3
If a line has a negative slope, it must pass through which 2 quadrants
II, IV
Rhombus definition
4 equal sides, angle of tilt can be anything. If angle is 90, is also a square
Slope of vertical line
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How do you find the equation of a line when you have a point and a slope
plug and solve for b (y = mx+b)
Regular polygon requirements
all equal sides, all equal angles
Area of parallelogram
You can’t find it with just the sides. You need the height (perpendicular to the base)
Area of a circular sector (slice of pie)
area of sector / piR^2
central angle / 360
length of circular arc
sum of all angles in an n-sided polygon
(n-2)180
surface area of rectangular solid
2hw+2wd+2dp
Area of equilateral triangle
