Math Is Fun Forum

Kage Suzuki

Member

Registered: 2021-05-26

Posts: 4

Trig Problem Help

In the diagram, tanC = 2.4. Find cos A.

                        C
                        |
                        |
                        |
A____________B

(Pretend there's a line from A to C, and angle ABC is a right angle)

Right now, what I have is:

tan(C)=AB/BC=2.4

cos(A)=AB/AC

Could I have a hint as to how to solve this, please? Thanks in advance!

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Trig Problem Help

hi Kage Suzuki

All right triangles that have that tangent are similar so take any easy triangle as an example.  eg AB = 24  BC = 10

So you can use Pythag. to calculate AC and hence give the value of cos.

If you try different values for AB and BC, you'll find you get the same answer.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Kage Suzuki

Member

Registered: 2021-05-26

Posts: 4

Re: Trig Problem Help

I got it, thank you so much!