Question

Use the triangle in the coordinate plane to find the perimeter.

Answer 1

find the distance using the formula

Answer 2

use the Pythagorus theorme to find each side

Answer 3

Find the length of AB, BC, CA using distance formula.
Add them up to get perimeter.

Answer 4

can you the length of AB ?

Answer 5

it is 13.45

Answer 6

AB is down 2 over 4?

Answer 7

\[AB = \sqrt{(5-1)^2 + (3-5)^2}\]

Answer 8

yes, so you have a triangle withs legs 2 and 4

use
c^2 = 2^2 + 4^2

Answer 9

20

Answer 10

you mean c^2 = 20

what is c ?

Answer 11

4.5

Answer 12

remember to take the square root of both sides

Answer 13

now make a note AB= 4.5

can you find AC ?

Answer 14

up 3 over 2

Answer 15

so c^2 is 13?

Answer 16

yes

Answer 17

c is 3.6

Answer 18

c= sqrt(13) = 3.6

so we now have

AB= 4.5
AC= 3.6

what is BC ?

Answer 19

down 5 over 2

Answer 20

c^2 is 29

Answer 21

c is 5.3

Answer 22

are you sure ?

Answer 23

sqrt 29 is 5.385

if you round it, you get 5.4

Answer 24

would the 5 be a negative?

Answer 25

no, for these problems, distance is always assumed to be positive.

the only problem is sqrt(29) is close to 5.4 than 5.3 (be careful about rounding)

finally, what is the perimeter ?

Answer 26

ok

Answer 27

13.5

Answer 28

yes

Answer 29

ok thanks

Answer 30

wait how do you round the sqrt?

Answer 31

see
http://www.khanacademy.org/math/algebra/linear-equations-and-inequalitie/more-analytic-geometry/v/distance-formula

for how they want you to do these problems (in case you don't have a graph, and can't count the squares)

Answer 32

by the first, second, or third number?

Answer 33

rounding is a rule:

if you round to the nearest tenth, you look at the digit to the right of the tenth digit

1.23
the 2 is in the tenths place. look at the digit to its right, the 3
if the digit is 5 or bigger round up. otherwise, just drop the fractions

example:
1.23912

round to the nearest tenth: look for the tenths place: 2. look to the right: a 3
3 is less than 5, so just drop all the digits to the left of 2. you get
1.2


example
1.2513
now you have a 5, so round up to
1.3

Answer 34

ok

Answer 35

so 5.830 it would be 5.9?

Answer 36

normally, when doing these problems, keep a few more digits than you really need, then round at the very end.

3 or 4 decimals are good to keep. then round to what the answer wants at the end

5.83 to the nearest ones is 6 (find the ones place:5 look to the right, see 8 is 5 or bigger and round up)

5.83 to the nearest tenths: find the tenths: 8, look to its right and see 3. 3 is less than 5
so just drop the digits to the right of 8 to get
5.8

Answer 37

ok help me with one more triangle please i dont understand it

Answer 38

ok, new post!