A cone is 15cm high and has a semi-vertical angle of 18 degrees. I'm quite good at trigonometry but I just don't get this question can someone help me? Thanks in advance
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the semi vertical angle of a cone is the angle between the axis and a line in the surface which passes through the apex.
Ok I think I get it. So I have to find the radius so if I make a right angled triangle... $\displaystyle \sin 18 = \frac {x}{15} $ $\displaystyle x = 15*\sin 18 $ $\displaystyle = 4.64 $ is this right?
Originally Posted by jgv115 Ok I think I get it. So I have to find the radius so if I make a right angled triangle... $\displaystyle \sin 18 = \frac {x}{15} $ $\displaystyle x = 15*\sin 18 $ $\displaystyle = 4.64 $ is this right? seems so... don't forget units especially on a test
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