Parallelogram
quadrilateral with both pairs of opposite sides congruent and parallel, opposite angles congruent, diagonals bisect each other,

Rhombus
parallelogram w/ 4 congruent sides, diagonals bisect angles, diagonal perpendicular

Rectangle
parallelogram w/ 4 right angles, diagonals congruent

Square
rhombus and rectangle therefore 4 congruent sides and 4 right angles, congruent perpendicular diagonals, diagonals bisect angles

Kite
quadrilateral, two pairs of adjacent sides congruent,, no opposite sides congruent, side angles congruent, diagonals are perpendicular, short one bisected, angles bisected

Trapezoid
quadrilateral w only 1 set of parallel sides

Isosceles Trapezoid
nonparallel sides congruent, adjacent angles congruent, diagonals congruent

3+ parallel lines
congruent segments of transversal

Similarity
AA~, SAS~ SSS~

Geometric mean
a/x=x/b any 2 positive numbers

altitude of a right triangle
makes 2 similar triagnles

side splitter thm
if a line is parallel to one side of a triangle and intersects with the other two sides then it divides those sides proportionally

Angle bisector thm
if a ray bisects an angle of a triangle then it divides the oposide side into town segmeents that are proportional to the other two sides

Pythagorean Thm
a^2+b^2= c^2

45-45-90
hypotenuse is sqrt2(leg)

Vector
magnitude and direction (degree, Direction, distance)

Area of Parallelogram
b(h)

Area Trapezoid
1/2h(b1+b2)

Area of Rhombus or Kite
1/2d1(d2)

Area of Regular Polygons
1/2ap

Area of any triangle
1/2bcsineA

Perimeters and Areas of Similar Figures
P=a/b A=a^2/b^2 (RATIOS)

Measure of Central Angle
360/n

Radius
center to circumference

Surface Area Cylinder
2(pi)rh+ 2(pi)r^2

Surface Area Pyramid
1/2pl+B

Surface Area Cone
(pi)rL+(pi)r^2

Volume of Cylinder
(pi)r^2h

Volume of Cone
1/3(pi)r^2h

Tangent
line that intersects at only one point on circle

Chord
segment with endpoints on circle

Secant
intersects at 2 places

coordinate plane circles
(x-h)^2+(y-k)^2=r^2

Distance formula
sqrt[(x2-x1)^2+(y2-y1)^2]

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