Two problems i can’t get is; 94-4.8 i know the answer is 89.2 but how?

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

At the height of about 212 meters one shell square is the tallest building in new orleans marlin is creating a scale model of this building using the scale 250 meters = 1 meter to the nearest tenth of a meter what will be the height of the scale model

Which point is an approximate extrapolation for x = 30 from the line of best fit?