Question

The diagram below shows the map of a mine.
How deep is the mine shaft?

8 by sin 25 degrees

8 by tan 25 degrees

8 cos 25°

8 tan 25°

Answer 1

are you familiar with the memory aid SOH-CAH-TOA?

Answer 2

yes kinda ..but not really it confuses me:/

Answer 3

Use the idea that

tan(angle) = opposite/adjacent


So what's the opposite side?

Answer 4

would it be 8?

Answer 5

that's the adjacent side (since it's along the same line as the angle)

Answer 6

the opposite side is BC, which is unknown at this point, so we'll call the opposite side x

Answer 7

do you see all this?

Answer 8

yea i do

Answer 9

so

tan(angle) = opposite/adjacent

tan(25) = x/8


Now solve for x

Answer 10

how would i do that?

Answer 11

well you're dividing by 8 on the right side, so you need to undo this and do what to both sides?

Answer 12

im still confused:/

Answer 13

basically, you undo the division by multiplication

Answer 14

so what do you multiply both sides by to move that 8 over?

Answer 15

(tan25)/8=0.058288457 right?

Answer 16

close, it's more like 8 * tan(25)

Answer 17

oops i divided
=3.730461265??

Answer 18

in this case, you leave it just like 8*tan(25)

Answer 19

since they want an exact answer

Answer 20

but if you wanted the approximate answer, then it's roughly 3.730461265 km deep

Answer 21

k thanks

Answer 22

yw