Question

A bridge across a valley is 150 m in
length. The valley walls make angles of
60° and 54° with the bridge that spans it,
as shown. How deep is the valley, to the
nearest metre?

Answer 1

is it 72.88 aprox??

Answer 2

nope...

Answer 3

well sorry !!!
thats as good as i can do :(

good luck !!

Answer 4

oh lol thanks anyways :)

Answer 5

this is the diagram

Answer 6

Use
x cot60 + x cot54 = 150

Answer 7

where x is the depth of the valley..

Answer 8

yeah lastday is right

Answer 9

Okay but what's "cot"

Answer 10

... is it the same as "cosine"

Answer 11

no... cot = 1/tan

Answer 12

cot = cos / sin

As the question says - ".. to the nearest metre.."
you can use cot 53 instead of cot 54

Answer 13

oh okay... thank you guys so much :)

Answer 14

@LastDayWork now... my problem
... plz.... help me...out....

Answer 15

The valley's depth is 115 meters.
Refer to the attached solution using Mathematica.

Answer 16

Okay;now I remember...there was a formula for cos 36 too

Answer 17

@tania98
Thank you for the medal.