Geometry Formulas

Question 1

center radius form

Answer 1

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

Question 2

standard form

Answer 2

x^2 + y^2 + x term + y term + number term = 0

Question 3

length of chords

Answer 3

(part1)(part 2) = (part1)(part2)

Question 4

length of secants and tangent

Answer 4

(outside)(whole) = (outside)(whole)

Question 5

central angle

Answer 5

central angle = arc

Question 6

inscribed angle

Answer 6

inscribed angle = 1/2 arc

Question 7

interior angle

Answer 7

interior angle = (arc+arc) / 2

Question 8

exterior angle

Answer 8

exterior angle = (arc - arc) / 2

Question 9

converting: degree to radian

Answer 9

deg/180 = radian / pi

Question 10

arc length

Answer 10

arc length = (degrees/360) (pi x d)

Question 11

area of a sector

Answer 11

area of sector = (deg/360) (pi r^2)

Question 12

slope formula

Answer 12

slope = y2-y1 / x2 -x1 = rise/run

Question 13

midpoint formula

Answer 13

(x1+x2 / 2, y1+y2 / 2)

Question 14

distance formula

Answer 14

d = square root of (x2-x1) ^2 + (y2-y1)^2

Question 15

equation of a line

Answer 15

y = mx+b m= slope b=y-intercept

Question 16

directed line segment

Answer 16

x = starting x + (fraction) (change in x)
y = starting y + (fraction) (change in y)

Question 17

area of a trapezoid

Answer 17

a = 1/2h(b1 + b2)

Question 18

population density

Answer 18

population density = population/area

Question 19

density

Answer 19

degree of compactness of a substance Mass divided by volume

Question 20

volume of a rectangular prism

Answer 20

v = l x w x h

Question 21

volume of a cube

Answer 21

v = e^3

Question 22

altitude proportion

Answer 22

proj/alt = alt/proj

Question 23

leg proportion

Answer 23

proj/leg = leg/whole hyp.

Question 24

sin angle

Answer 24

opposite/hypotenuse

Question 25

cos angle

Answer 25

adjacent/hypotenuse

Question 26

tan angle

Answer 26

opposite/adjacent

Question 27

law of sines

Answer 27

a/sin a = b/sin b = c/sin c

Question 28

sine and cosine are _____ for complementary angles

Answer 28

equal

Question 29

scale factor

Answer 29

scale factor = image/preimage or new/old

Question 29

scale factor

Answer 29

scale factor = image/preimage or new/old

Question 30

median of a trapezoid

Answer 30

1/2 (base1 + base2)

Question 31

rotational symmetry

Answer 31

360/#of ways it can sit there and look the same

Question 32

horizontal and vertical lines

Answer 32

Horizontal line
O slope (zero slope)
Y = # is the equation of every horizontal line

Vertical lines
Undefined slope (no slope)
X = # is the equation of every vertical line

Question 33

rules of the lengths of the sides of any triangle

Answer 33

given 3 sides:

small side + small side > largest side

given 2 sides:
difference < 3rd side < sum

Question 34

sum of interior angles of a polygon

Answer 34

sum = 180 (n -2)

Question 35

sum of exterior angles of a polygon

Answer 35

sum = 360

Question 36

one interior of a regular polygon

Answer 36

180 (n-2) / n

Question 37

one exterior angle of a regular polygon

Answer 37

1 exterior angle = 360/n

Question 38

adjacent interior and exterior angles of a polygon

Answer 38

interior angle + exterior angle = 180