Question

HELP?
The diagram shows a section of a bridge between the points A and K. The length of line segment AK 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.

Answer 1

@Bigbosssaint21

Answer 2

@jigglypuff314

Answer 3

In geometry, drawing the diagram and filling all given information is the best first step.
I'll help you get started by showing a diagram everyone can see.
Please complete the diagram by showing all pertinent information given in the question.

Answer 4

i dont understand what you want me to do

Answer 5

how do i find the length

Answer 6

It will help you solve a geometry (or trigo) problem if you show all given information on the diagram. Otherwise the problem will look difficult.

I'll do the first step:
"The length of line segment AK is 640 meters."
so


Please continue reading the question and put all information on the diagram. After that, you can start solving the problem.

Answer 7

CF = 40?

Answer 8

@jigglypuff314

Answer 9

@jim_thompson5910

Answer 10

@pooja195

Answer 11

@ganeshie8

Answer 12

@mjdennis

Answer 13

What three thins add up to AK?

Answer 14

you can find the lengths of AC , CF and FK by forming an equation
AC + CF +FK = 640

you also know that 2AC = CF = 2FK

so you can find the lengths of these 3

Answer 15

As all the triangles are similar you can then find the length of the pillar DH and the area of triangle CDF.

Answer 16

if we let length of AC = x then CF = 2x and FK = x

so
x + 2x + x = 640

solve for x

Answer 17

is there a formula

Answer 18

can you solve the above for x?

Answer 19

im not sure how because there is only 2 given numbers

Answer 20

what is x + 2x + x equal to?

Answer 21

640

Answer 22

what I mean is simplify x + 2x + x

Answer 23

we are trying to solve the equation - find value of x

Answer 24

whats the first step in finding x

Answer 25

- simplifying x + 2x + x

Answer 26

so x will be just 1 number right

Answer 27

yea

Answer 28

180?

Answer 29

160?

Answer 30

4x = 640
x = 640/4 = 160

Answer 31

so the area of CDF is 160?

Answer 32

No 160 is the length of AC and FK and CF = 2*160 = 320.

Answer 33

oh alright! so thats the answer? 320?

Answer 34

No we are asked for the area of the triangle CDF

the triangles are similar so as i explained earlier we can now find the height of triangle CDF (DH)

Answer 35

would the height be 40?