Question

Will fan and medal!
Solve right triangle ABC: C= 90*, A= 15*, and side b= 17.6.
I found that angle B= 75*
but how do I use tangent and cosine to find the sides of the triangle?

Answer 1

sin B = opposite side/ hypotenuse
sin 75 = 17.6 / h
h * sin 75 = 17.6
h = 17.6 / sin 75

now grab ur calculator and work it out

Answer 2

Note I could have let hypotenuse = c

you can find the length of the other side a by using tan 15 = a / 17.6

Answer 3

i got 18.220860…. is that right?

Answer 4

the was just an three dots.

Answer 5

18.22 is ok - correct to 2 decimal places

Answer 6

I think i was supposed to use tangent..the answer wouldn't have came out the same if i would have used tangent, right?

Answer 7

or was that for side c??

Answer 8

to find the hypotenuse you use sine or cosine

Answer 9

that was for side c

Answer 10

oh okay! that makes sense.

Answer 11

c = hypotenuse

Answer 12

gottcha

Answer 13

i used h by really it was better to use c (opposite angle C)

Answer 14

did you want to use the cosine to find c not the sine?

Answer 15

no, that's fine. I just forgot i could use sine as well for hypotenuse. what about side a? How would I find that?

Answer 16

to find side a you can use the tangent
tan A = opposite / adjacent
tan 15 = a / 17.6
a = 17.6 * tan 15

Answer 17

do you know SOH-CAH-TOA - helps you remember what each trig ratio means

Answer 18

Oh yeah, now i feel silly for not seeing that one! hahaha

Answer 19

Yes! Thank you so much for your help!

Answer 20

yw