I just don't get this in general
mj will be 60 dagree for the others use the hypatos formula
I hope this helps you in 30-60-90 triangle 30 => k=HJ60=> k square root of 3=HI90=> 2k=JI2k=12 square root of 23HJ=k=6 square root of 23HI=k square root of 3=6 square root of 69m (J)=60