Finding the Fourth Proportional to 1,089.21, 1,502.61 and 646.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,089.21 : 1,502.61 = 646.86 : x
2. Step 2: Convert to fraction form
   1,089.21/1,502.61 = 646.86/x
3. Step 3: Cross multiply
   1,089.21x = 1,502.61 × 646.86
4. Step 4: Simplify right side
   1,089.21x = 971,978.30
5. Step 5: Solve for x
   x = 971,978.30/1,089.21
6. Step 6: Final answer
   x = 892.37