AREA BY PLANIMETER

1. To check a planimeter, a 3cm by 3cm square was drawn on a piece of paper and planimetered, with a difference in reading of 581. Later the planimeter was used to determine the area of a watershed portrayed in a map drawn to scale of 1cm=50m. If the difference in planimeter readings is 1496, determine the area of the watershed.
2. A draftsman drew a 10cm square on a piece of paper and traced it with a planimeter. The initial reading on the planimeter was 2070 and the following were the readings for the three trials made: 3680, 5289 and 6901. He then used this planimeter to determine the excavated area of a borrow pit marked off on a map drawn to a scale of 1cm=100m. Determine the area of the borrow pit if this time the initial reading was 0280 and the following were the readings for four trials: 1065, 1851, 2634, and 3422.