Finding the Fourth Proportional to 1,620.09, 2,235.72 and 921.46

Step by Step Solution

1. Step 1: Write the proportion equation
   1,620.09 : 2,235.72 = 921.46 : x
2. Step 2: Convert to fraction form
   1,620.09/2,235.72 = 921.46/x
3. Step 3: Cross multiply
   1,620.09x = 2,235.72 × 921.46
4. Step 4: Simplify right side
   1,620.09x = 2,060,126.55
5. Step 5: Solve for x
   x = 2,060,126.55/1,620.09
6. Step 6: Final answer
   x = 1,271.61