Help finding sides with other angles of other triangles nearby

**PhizKid** · December 17th 2012, 01:56 AM

I have to find side 'R'
L = 6.10 meters, theta = 36.9 degrees, and phi = 53.1 degrees.

I don't see any way I can attempt this, I'm very rusty with my trig. We have a known side and a right angle, but I don't see how I can make any other angles (since we only have one side I'm assuming I need to get an angle somewhere

**earboth** · December 17th 2012, 10:10 AM

Originally Posted by PhizKid

I have to find side 'R'
L = 6.10 meters, theta = 36.9 degrees, and phi = 53.1 degrees.

I don't see any way I can attempt this, I'm very rusty with my trig. We have a known side and a right angle, but I don't see how I can make any other angles (since we only have one side I'm assuming I need to get an angle somewhere

1. I've modified your sketch a little bit (see attachment

2. According to the definition of the Sine function in a right triangle you'll get:

$\frac RL = \sin(90^\circ - \theta)$

3. Since L and $\theta$ are known you can determine R.