Question

The diagram shows a section of a bridge between the points A and K. The length of line segment is 640 meters. ∆ABC, ∆CDF, and ∆FJK are similar, and 2AC = CF = 2FK. The first pillar,--BG , is 20 meters tall.
The area of ∆CDF is___________ square meters.
link-https://cdn.ple.platoweb.com/EdAssets/1ede0da051bd4a47b13ca7013501ae97?ts=635405481637200000

Answer 1

Try using the pythagorean theorem. So, plug in what you have for ABC

Answer 2

idk how to do that lol i bombed the class

Answer 3

The Pythagorean theorem states that the square of the hypotenuse in right triangle is equal to the sum of the squares of the other two sides. This is expressed as a^2 + b^2 = c^2.

Answer 4

Okay well the pythagorean theorem is where you have an triangleand either of the angles are A B or C.

Answer 5

oh i remember that formula now lol u jogged my memory

Answer 6

No I dont think you need pythagoras in this case

Answer 7

i really need help on getting this im so close to passing this assighnment by this question

Answer 8

Area of CDF = 1/2 x CF x DH

Answer 9

what is ---cf and ---dh equal it doesnt say

Answer 10

is it basically 1/2 base times hight

Answer 11

well AC+CF+AK = 640m correct?

Answer 12

it says --ak is 640 all together

Answer 13

i meant AC+CF+FK = 640

Answer 14

happy with that?

Answer 15

yep

Answer 16

OK now AC = CF/2 & FK = CF/2 right?

Answer 17

yes

Answer 18

So now we have CF/2 + CF + CF/2 = 640
and from here you can work out CF!

Answer 19

so would you divide to find cf

Answer 20

by 3 maybe

Answer 21

no. what does the LHS of the equation work out to?

Answer 22

213?

Answer 23

no thats way off. What does CF/2 + CF + CF/2 become?

Answer 24

idk im sorry

Answer 25

640?

Answer 26

in total

Answer 27

Thats the RHS. Im asking you what the LHS simplifies to?

Answer 28

one half of CF + CF + one half of CF = what in terms of CF

Answer 29

320?

Answer 30

320 is what?

Answer 31

half of segment cf plus cf/2

Answer 32

so CF/2 + CF/2 = 320 iS THAT WHAT YOU MEAN?

Answer 33

yes

Answer 34

Very Good. So we have CF/2 + CF/2 = CF = 320 m

Now we have to find DH

Answer 35

is says ---bg is 20

Answer 36

If CF = 2AC then DH would equal 2BG because they are similar triangles, correct?

Answer 37

so 40? for height

Answer 38

Brilliant, so now you can work out the area!!

Answer 39

ight 1 sec

Answer 40

i got 6400

Answer 41

Fabulous, well done

Answer 42

is it in square meters?

Answer 43

Yep

Answer 44

thank you so much

Answer 45

no problem, it was a pleasure. i hope that helps you to understand things

Answer 46

it does thanks