What is the sum of arithmetic series 19+25+31+37+… Where n=9 ?

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

Terri makes a quilt using three sizes of fabric squares the side lenght of each fabric square is the square root of the area

Can someone check if i did this correct. it’s number 4 if you’re wondering.