Pls help me, i am very confused and i have no idea what to do, i will give brainliest and 35 points you only have to do part one and part three, i can do part two.​

Answer this 30 points and brainliest!

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

Askateboard ramp is in the shape of a right triangle what is the height of the ramp