Question

In ABC, C is a right angle, what is the measure of x?

Answer 1

I know you have to use the sin, tan, cos formulas but I don't understand how to use them?

Answer 2

you need to find the angle right?

Answer 3

Yes

Answer 4

Well the measure of it I mean

Answer 5

the measure as in , in degree? right,,

Answer 6

sin = sOH Opposite over Hypotenuse
cos= cAH Adjacent over Hypotenuse
tan= tOA opposite over Adjacent

for this diagram, which formulas do you think would suit to get the angle x

Answer 7

Yes in degrees, Opposite over adjacent

Answer 8

since the angle is in betweel of length AC and AB, so why dont you use the Adjacent over hypotenuse(cos formulae) ? It would be easier since you'll be dealing with one unknown :)

Answer 9

How do I use it since the hypotenuse is unknown? Isn't the 8 the opposite and the 21 the adjacent?

Answer 10

opposite of x would be the line CB.. 8 is the adjacent.. and 21 is obviously the hypotenuse.. are you confused on that part?

Answer 11

So I should divide 21 by 8 ?

Answer 12

since you're using the cos rule, cAH
Adjacent = 8
Hypo = 21

so it would be 8/21

cos x=8/21

Answer 13

http://www.wisc-online.com/objects/ViewObject.aspx?ID=TMH401 this might help you.. i think

Answer 14

yes

Answer 15

When I do that I get .3809... and abunch of other numbers

Answer 16

yes.. you got the first step right..

Answer 17

remember you still have your cos on your left.. what do you do with it?

Answer 18

x= shift cos (8/21)

Answer 19

is the answer supposed to be in decimal points?

Answer 20

The answer is suppose to have a decimal in it, I'm confused with the 'cos'

Answer 21

okay, the cos part, since you want to find the x, you cant have the cos together there, so to remove you must inverse the cos and bring it to your right,
it's like multiplying, when you transfer to the other side, it becomes division, right?

for cos, we "shift cos" same goes with tan and sin :)

Answer 22

so what's the final answer do you get?

Answer 23

Ah, I'm so confused

Answer 24

I'm so sorry. Okay just keep in mind, like this