Triangle - finding side b?

[mcarthyryan]

Hi Guys,

Another question has come up, which I am struggling with. I have found two answers which I calculated as:

First Answer:
c^{2 =} a² + b²
b² = c² - a²

b = sqrt(c² - a²⁾


Second Answer:
sinθ = b/c
b = c x sinθ

Third Answer:
I used the equation:
tanθ = a/b
b = a x tanθ ----- but this option isn't there. Can anyone point in in the right direction where to go to try to find the third answer please?

I know tanθ = sinθ / cosθ, but I cannot use that either.






Thanks a lot

 

[Harry_the_cat]

Hi Guys,

Another question has come up, which I am struggling with. I have found two answers which I calculated as:

First Answer:
c^{2 =} a² + b²
b² = c² - a²

b = sqrt(c² - a²⁾


Second Answer:
sinθ = b/c
b = c x sinθ

Third Answer:
I used the equation:
tanθ = a/b
b = a x tanθ ----- but this option isn't there. Can anyone point in in the right direction where to go to try to find the third answer please?

I know tanθ = sinθ / cosθ, but I cannot use that either.






Thanks a lot

If the angle down the bottom is PHI, then the angle up the top must be 90 - PHI....right?

Now write an expression for tan (90 - PHI), and then rearrange.

 

[mcarthyryan]

ooooh yes!

I see now thank you.

Answer is b = c cos (90 - θ)



Thank you for the help again.