A108 inch board is cut into two pieces one piece is five times the length of the other find the length of the shorter piece

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

In the diagram, gef and hef are congruent. what is the value of x

Can someone explain to me how to do