# Math Help - Easy Easy Trig help

1. ## Easy Easy Trig help

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?

2. the semi vertical angle of a cone is the angle
between the axis and a line in the surface which passes through the apex.

3. Ok I think I get it. So I have to find the radius

so if I make a right angled triangle...

$\sin 18 = \frac {x}{15}$

$x = 15*\sin 18$

$= 4.64$

is this right?

4. 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...

$\sin 18 = \frac {x}{15}$

$x = 15*\sin 18$

$= 4.64$

is this right?
seems so...
don't forget units especially on a test