# Thread: Sine, cosine and tangent

1. Hi guys.....

As elementary as this may seen to most of you, and once you have picked yourself up from the floor after laughing, i could do with some help understanding sine, cosine and tangent's.

First question regarding them: Is it only right angled triangles that this applies to?

Okay next...... I have drawn a right angled triangle where the angle is measured 69 degrees and the hypotenuse is 8.5cm and the opposite is 8cm.

Now, calculating the Sine manually (Opposite/Hypotenuse) therefore (8/8.5) I get the figure of........

0.9411764706

However, when entering 69 degrees into my calculator and using the Sine function, I get a figure of.......

^-.1147848138

Hmmm..... something isnt going quite my way, or I am doing something wrong? any help would be great. Thanks.

2.

4. aaah okay. How many radians are there in a full circle ?

6. the conversion from degrees to radians is quite simple

7. Your calculator probably has an option to calculate trig function in degrees.

8. harold is correct but it is better to become familiar with radians early.

radians actually have a geometric interpretation where as the degree is an arbritary division of the circle.

radians are used more often in mathematical text.

9. Okay thanks guys.

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