Extracted text: In a catchment area, six rainfall stations are situated as shown in the figure below. Rainfall depths (cm) in year 2016 were as follows: A=22, B=35, C=30, D:29, and E=26, F= 21. Determine the average annual precipitation using the Thiessen-polygons method. 50 km 25 km 20 km + 20 km 50 km 26 km