Finding the Fourth Proportional to 1,620.25, 2,235.89 and 912.11

Step by Step Solution

1. Step 1: Write the proportion equation
   1,620.25 : 2,235.89 = 912.11 : x
2. Step 2: Convert to fraction form
   1,620.25/2,235.89 = 912.11/x
3. Step 3: Cross multiply
   1,620.25x = 2,235.89 × 912.11
4. Step 4: Simplify right side
   1,620.25x = 2,039,361.89
5. Step 5: Solve for x
   x = 2,039,361.89/1,620.25
6. Step 6: Final answer
   x = 1,258.67