28 terms

# Geometry

Ms. Bira, Per.6, Abraham Lincoln High
###### PLAY
point slope
y-y1=m(x-x1)
perpendicular
lines that intersect at right angles, slope is opposite reciprocal
solving by substitution
-solve one of the equations for one of the variables
-substitute the expression into the other equation
-solve
-find the value of the other variable
-check (this is where the lines cross)
vertex
-b/2a
zeroes
substitute y as 0
[-b ± √(b² - 4ac)] / (2a)
factoring
x problem set, top=c, bottom=b
factoring when a=/=1
x problem set + box set, top left=a, top right& bottom left=x set answers, factor
line of symmetry
subtract zeroes, divide by 2
rotation
(mathematics) a transformation in which the coordinate axes are rotated by a fixed angle about the origin
reflection
A transformation that "flips" a figure over a mirror or reflection line.
translation
A transformation that "slides" each point of a figure the same distance in the same direction.
distance formula
d = √[( x₂ - x₁) + (y₂ - y₁)]
properties of kites
1) two disjoint pairs of consecutive sides are congruent by definition 2) the diagonals are perpendicular 3) one diagonal is the perpendicular bisector of the other 4) one of the diagonals bisects bisects a pair of opposite angles 5) one pair of opposite angles are congruent
midpoint formula
(x₁+x₂)/2, (y₁+y₂)/2
triangle congruence
SSS, SAS, ASA, AAS, and HL
similar polygons
if corresponding angles are congruent and corresponding side lengths are proportional
SohCahToa
Area of a Trapezoid
a=1/2h(b1+b2)
Area of a Kite
A=½d₁d₂
inscribed arc
ins=1/2arc
centrical arc
cent=arc
outside angle
big arc - little arc / 2
sum of interior angles
(n-2)180
inside angle
big arc + little arc / 2
30-60-90
A special right triangle with one leg being x, the leg opposite the 60° angle being x√3, and the length of the hypotenuse 2x.
45-45-90
x, x, x√2
exterior angle
360/n