Flashcards in Geometry Deck (47):

1

## Triangles Perimeter

### P = A + B + C

2

## Triangle Area

### A = (B×H) ÷ 2

3

## Specific triangles

### 30-60-30 = 1:sqrt(3):2 - 45-45-90 = 1:1:sqrt(2)

4

## Square properties

### All opposites sides are parallel and have the same length. All angles are 90°. Diagonal have the same length, intersect at 90° and bisect each other. Interior angles add up to 360°.

5

## Square area

### A = s2

6

## Square perimeter

### P = 4s

7

## Square key shapes

### Diagonals create two 45-45-90 isoceles right triangles.

8

## Rectangle properties

### All opposites sides are parallel. Opposite sides are the same length. All angles are 90°. Diagonals are the same length and bisect each other. Interior angles add up to 360°.

9

## Rectangle area

### A = l × w

10

## Rectangle perimeter

### P = 2l + 2w

11

## Rectangle key shapes

### Diagonals create 2 right triangles.

12

## Parallelogram properties

### All opposites sides are parallel. Opposite sides are the same length. Opposite angles are equal. Diagonals bisect each other. Interior angles add up to 360°.

13

## Parallelogram area

### A = b × h

14

## Parallelogram perimeter

### P = 2a + 2b

15

## Parallelogram key shapes

### Right triangle needed to find the height.

16

## Trapezoid properties

### 2 sides are parallel. Interior angles add up to 360°.

17

## Trapezoid area

### A = 1/2 (b+c)h with b and c the length of the parallel sides.

18

## Trapezoid perimeter

### P = a + b + c + d

19

## Trapezoid key shapes

### Right triangle needed to find the height.

20

## Sum of angles of a polygon

### SoA = (n-2)×180 (with n the number of sides)

21

## Circle area

### A = πr^2

22

## Circle circumference

### C = 2πr

23

## Circle arc length

### AL = 2πr ( x/360 ) with x the central angle measure

24

## Circle - Similar inscribed angles

### All inscribed angles that extend to the same arc or same two points on a circle are equal.

25

## Circle - Central angle x vs. inscribed angle y

### Any central angle that extends to the same arc or same two points on a circle as does an inscribed angle is twice the size of the inscribed angle. x = 2y

26

## Circle - Triangles inscribed in a semicircle

### Any triangle inscribed in a semicircle with the circle diameter as longer side is always a right triangle.

27

## 3D figures - Volume

### V = (area of 2-D surface)×h

28

## Cube volume

### V = s3

29

## Cube surface area

### SA = 6s2

30

## Cube longest length within

### L = sqrt(3s^2)

31

## Rectangular solid volume

### V = lwh

32

## Rectangular solid surface area

### SA = 2lw + 2lh + 2hw

33

## Rectangular solid longest length within

### L = sqrt( l^2 + w^2 + h^2 )

34

## Cylinder volume

### V = π×r^2×h

35

## Cylinder surface area

### SA = 2(πr^2) + 2πrh

36

## Cylinder longest length within

### L = sqrt(4r^2 + h^2)

37

## Cylinder longest length within

### L = sqrt(4r^2 + h^2)

38

## Cylinder longest length within

### L = sqrt(4r^2 + h^2)

39

## Sphere volume

### V = (4/3)πr^3

40

## Sphere surface area

### SA = 4πr^2

41

## Sphere longest length within

### L = 2r

42

## Slope intercept formula

### y = mx + b with m the slope, b the y-intercept and (-b/m) the x-intercept.

43

## Slope of a line

### Δy / Δx = (y2 - y1) / (x2 - x1)

44

## x- and y-intercepts

### 1 - Use y = mx + b formula. 2 - Set x equal to 0 to find the y-intercept. Set y equal to 0 to find the x-intercept.

45

## Calculating intersections of two lines

### Set both equations equal to each other and resolve. (l1) : y=ax+b ; (l2) : y=mx+p --> ax+b=mx+p

46

## Distance between any two points

### (p1) : (x1, y1) ; (p2) : (x2, y2) --> d(p1, p2) = sqrt( (Δx)^2 + (Δy)^2 ) = sqrt( (x1-x2)^2 + (y1-y2)^2 )

47