Estimation of Missing Rainfall Data - Hydrology

The normal annual rainfall at stations a, b, c, and d in a basin are 80.97, 67.59, 76.28 and 92.01 cm respectively. In the year 1975, the station D was inoperative and the stations a, b, and c recorded annual precipitations of 91.11, 72.23 and 79.89 cm respectively. Estimate the rainfall at station d in that year.
‪@hydraulicsandhydrologytutorial‬ ‪@hydrologyvideos8253‬