# Very basic trig question - help an idiot?

• February 12th 2014, 10:44 AM
jonathan256
Very basic trig question - help an idiot?
Hi guys,

I have a really basic trig question that I need help with as shown in the diagram below! I'd love to be able to have a go at it as I know I should in these forums but I really can't attempt to do it at all which is a bit embarrassing.

The angle I need is the red highlighted one, or the opposite one.

I hope you can view the photo easily enough!? Any queries please post on here.

Attachment 30170

If I am reading your picture correctly, the "red line" appears to cross the line marked 20 m half way across that 7 m section. So you have a "height" of 20 with a width of 10+ 3.5= 13.5 m. Since tangent is "height divided by width" we have $tan(\theta)= \frac{20}{13.5}= 1.48148$... so that $\theta= 0.977$ radians or 56 degrees.