Finding the Fourth Proportional to 1,620.17, 2,235.83 and 921.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,620.17 : 2,235.83 = 921.54 : x
2. Step 2: Convert to fraction form
   1,620.17/2,235.83 = 921.54/x
3. Step 3: Cross multiply
   1,620.17x = 2,235.83 × 921.54
4. Step 4: Simplify right side
   1,620.17x = 2,060,406.78
5. Step 5: Solve for x
   x = 2,060,406.78/1,620.17
6. Step 6: Final answer
   x = 1,271.72