-4.3g=25.8 what is the awnser

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

When you answer this can you explain

M.xyz =radians. covert this radian measure to its equivalent measure in degrees.