# Please help new to trigonometry

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• May 2nd 2009, 08:20 PM
Rao
Please help new to trigonometry
Hello

Hi I am learning trigonometry if someone can do these for me I'll be able to do the rest thank you very much(Doh) .

http://img149.imageshack.us/img149/8830/mathm.jpg

These three question Thank you very much.(Crying)(Doh)
• May 3rd 2009, 03:00 AM
pickslides
Quote:

Originally Posted by Rao
Hello

Hi I am learning trigonometry if someone can do these for me I'll be able to do the rest thank you very much(Doh) .

http://img149.imageshack.us/img149/8830/mathm.jpg

These three question Thank you very much.(Crying)(Doh)

Hi there if $sin(\theta) = \frac{3}{11}$

You must consider a right angled triangle and the ratio

$sin(\theta) = \frac{opposite}{hypotenuse}$

Using pythagora's theorem the thrid side must be as follows:

$\sqrt{11^2-3^2}$

$\sqrt{112}$

Now you can use these to find

$cos(\theta) = \frac{adjacent}{hypotenuse}$

$sin(\theta) = \frac{opposite}{adjacent}$