I used a calculator and just rounded this number 1.30769230769
if the number is five or higher then you would round the number next to the 7. So 7 rounded 0 is 1.31. Sorry i tried to explain it in the best way possible!
dihedral angle is the angle between two intersecting planes. So, the angle with the same measure of the dihedral angle formed by plane DAJ and plane ABC is angle JAB
