Flashcards in Perimeter/area Deck (14):

0

## Define a perimeter:

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A perimeter is the length of the outline of a geometrical figure.

1

## How do you calculate the perimeter of a square?

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4xs (s is short for side)

Ex:s=5

5x4

20

2

## How do you calculate the perimeter of a rectangle?

###
There are three methods:

-h+h+w+w (h is short for height, w is short for width)

-hx2+wx2

-(h+w)x2

Ex:h=4 w=5

(4+5)x2

9x2

18

3

##
Perimeter of a square of s=6?

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6x4

24

4

## Perimeter of a rectangle h=7 w=10?

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(7+10)x2

17x2

34

5

## Define area:

### Area is all the part that is inside the geometrical figure.

6

##
How do you calculate the area of a square?

###
sxs

Ex:s=5

5x5=25

7

## How do you calculate the area of a rectangle?

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hxw

Ex:h=6 w=5

6x5=30

8

## What is pi ( pronounciation: pie)?

###
Pi is named after the greek letter pi. In maths, pi is equal to ~3.14.Actually, it is impossible to say exactly what pi is equal to since the digits go on for ever with no repetition at all. The first digits are 3.14159265358...

Pi is used for a lot of things, but mainly for measuring the perimeter and area of circles.

The first people to use it were the Greeks.

9

## Define the radius of a circle:

### The radius is the line that goes from O to the edge of the circle.The radius itself is written r. The measure of the radius is written as R.

10

## Define a chord in a circle.

### A chord is the line that goes from one edge of the circle to the other.

11

## Define the diameter in a circle:

### A diameter is the longest chord, it passes by O and is exactly the double of the radius.

12

## How do you measure the perimeter of a circle?

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Pi x r x 2

Ex: r=5

Pi x 5 x 2

Pi x 10 This is the exact value.

You cannot get closer to the exact value.

3.14x10

31.4 This is the approximate value.

13