Thread: How far was the pilot from starting point?

Please help me, I'm not really good with trigo..

A pilot flew for 210 miles at 21degree and then 147 miles at 162 degree. How far was he from starting point?

start by making a sketch of the problem ... looks to me like a task involving the cosine law.

Thanks for the diagram sir..
∠ABC = 21 + (180 - 162) = 39° Is that correct sir?

Originally Posted by Adikz

Thanks for the diagram sir..
∠ABC = 21 + (180 - 162) = 39° Is that correct sir?

if you mean the acute angle at the top of the position triangle, yes.

Using the law of cosines:
This will be my new formula right?

b = √(210² + 147² - 2 * 210 * 147 * cos 39°)

formula is a^2+b^2 - c^2 / 2ab = cos 39 deg Solve for c given a and b

Originally Posted by Adikz

Using the law of cosines:
This will be my new formula right?

b = √(210² + 147² - 2 * 210 * 147 * cos 39°)

correct

Thanks..