Finding the Fourth Proportional to 1,099.30, 1,648.14 and 521.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,099.30 : 1,648.14 = 521.50 : x
2. Step 2: Convert to fraction form
   1,099.30/1,648.14 = 521.50/x
3. Step 3: Cross multiply
   1,099.30x = 1,648.14 × 521.50
4. Step 4: Simplify right side
   1,099.30x = 859,505.01
5. Step 5: Solve for x
   x = 859,505.01/1,099.30
6. Step 6: Final answer
   x = 781.87