Question

MEDAL+FAN,help please!
In the figure, if CD = 15 cm, then BC ≈_____cm
6.6
11
21.6
34.7

Answer 1

https://cdn.ple.platoweb.com/EdAssets/8f746af703b945dc88cb674fd21d2a2d?ts=635369963867900000

Answer 2

Hi!!
is this trig?

Answer 3

yup, well partly geometry but yea! :)

Answer 4

so the first two make no sense

Answer 5

Do you think you could help me out please?

Answer 6

yeah i think so

Answer 7

alright, well yea i looked at the angle so it has to be greater than 15

Answer 8

lets call CD \(x\)

Answer 9

no sorry CD = 15, lets call BC \(x\)

Answer 10

and \(AB\) lets call \(y\)

Answer 11

so \[\tan(40)=\frac{x}{y}\] or \[y=\frac{x}{\tan(40)}\]

Answer 12

tan40 =.8390996312

Answer 13

oops i am messing this up
sorry \[\tan(40)=\frac{y}{x}\] so \[y=x\tan(40)\]

Answer 14

no worries, were human, we make mistakes ^^

Answer 15

also \[tan(70)=\frac{y}{15}\] so \[y=15\tan(70)\]

Answer 16

since it is the same \(y\) for both it must be the case that \[x\tan(40)=15\tan(70)\]

Answer 17

15tan(70) = 41.21216129

Answer 18

yeah i need to go back with pencil and paper

Answer 19

lol its okay, i get confused on just computer to

Answer 20

\[\tan(40)=\frac{y}{x}\]\[y=x\tan(40)\]
\[\tan(70)=\frac{y}{15}\]
\[y=15\tan(70)\]

Answer 21

so \[\tan(40)=\frac{15\tan(70)}{x}\]

Answer 22

getting the same answer as before \[x=\frac{15\tan(70)}{\tan(40)}\]

Answer 23

i got 130.093641

Answer 24

ok i see my mistake

Answer 25

\[\tan(40)=\frac{y}{15+x}\]

Answer 26

i think your the most human helper here, everyones like a robot that dont make mistakes

Answer 27

and \[y=15\tan(70)\] so
\[tan(40)=\frac{15\tan(70)}{15+x}\]

Answer 28

we gotta solve that for \(x\) no problem

Answer 29

\[\frac{15+x}{15\tan(70)}=\frac{1}{\tan(40)}\]
\[15+x=\frac{15\tan(70)}{\tan(40)}\]
\[x=\frac{15\tan(70)}{\tan(40)}-15\]

Answer 30

i hope 34 is an answer choice
http://www.wolframalpha.com/input/?i=15tan(70)%2Ftan(40)-15

Answer 31

34.7! lol

Answer 32

ok i guess that will do it unless i made another mistake

Answer 33

alright thank you! :)

Answer 34

\[\color\magenta\heartsuit\]