Finding the Fourth Proportional to 1,086.02, 1,628.34 and 921.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.02 : 1,628.34 = 921.55 : x
2. Step 2: Convert to fraction form
   1,086.02/1,628.34 = 921.55/x
3. Step 3: Cross multiply
   1,086.02x = 1,628.34 × 921.55
4. Step 4: Simplify right side
   1,086.02x = 1,500,596.73
5. Step 5: Solve for x
   x = 1,500,596.73/1,086.02
6. Step 6: Final answer
   x = 1,381.74