+208 Hey there!
We know that near H, G, D and C that these angles will add to give 180, we also know that the two angles at the tops of the triangles near F will be equal to eachother. Finally we know that the sum of angles in a triangle is equal to 180. Using this you can find all the angles needed to find angle B. Give it a crack and let me know how you go!
Hope this helped :)
