Question

GIVE MEDAL!!

In right ∆ABC, m B = 90°, m C = 40°, and BC = 10. What are the other two side lengths of the triangle?

AC = 13.1, AB = 8.4

AC = 18.7, AB = 15.8

AC = 14.3, AB = 10.2

AC = 15.6, AB = 11.9

Answer 1

We can use Sine, Cosine, and Tangent to find the remaining sides..

Answer 2

\(\sf Sine=\dfrac{Opposite}{Hypotenuse}\)

\(\sf Cosine=\dfrac{Adjacent}{Hypotenuse}\)

\(\sf Tangent = \dfrac{Opposite}{Adjacent}\)

Here, we are given the adjacent side, and we want to find the opposite and the hypotenuse.

Answer 3

Hehe, it would be if you got it yourself :P

Answer 4

o..k

Answer 5

umm..

Answer 6

So to find the hypotenuse, we can use cosine.

\(\sf Cosine=\dfrac{Adjacent}{Hypotenuse}\)

Plug in what we know:

\(\sf cos(90^o) = \dfrac{10}{x}\)

Answer 7

Hmm..I think that's right..I'm not sure about which angle to use..I haven't done this in a while..

Answer 8

its ok

Answer 9

Okay, 90 degrees is wrong..

Answer 10

Hold on a minute

Answer 11

k

Answer 12

Okay, I think we use 40 degrees..

Answer 13

So:

\(\sf cos(40^o) = \dfrac{10}{x}\)

Type in \(\sf cos(40^o)\) into your calculator, tell me what you get.

Answer 14

i dont have a scientific one ..its ok ill guess but thx for help ill give tht medal :)

Answer 15

You can use google, just type in "cos 40 degrees"

Answer 16

kk

Answer 17

a big decimal so ill put 0.766

Answer 18

Yep, so we have:

\(\sf 0.766 = \dfrac{10}{x}\)

Solve for 'x'

Answer 19

so i times the decimal and 10?

Answer 20

or divide

Answer 21

Well, you can switch 'x' and 0.766 around.

\(\sf x = \dfrac{10}{0.766}\)

So just divide

Answer 22

13.1?

Answer 23

it was a big decimal so i round it and got tht

Answer 24

Sorry, my internet just went out for a few seconds there.

Answer 25

Yep, 13.1 is corret.

Answer 26

correct*

Answer 27

That's our hypotenuse.

Answer 28

its a!!!

Answer 29

Yes, I think that's correct.

Answer 30

thx for the help :)

Answer 31

Np