Finding the Fourth Proportional to 1,087.78, 1,631.61 and 384.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.78 : 1,631.61 = 384.94 : x
2. Step 2: Convert to fraction form
   1,087.78/1,631.61 = 384.94/x
3. Step 3: Cross multiply
   1,087.78x = 1,631.61 × 384.94
4. Step 4: Simplify right side
   1,087.78x = 628,061.87
5. Step 5: Solve for x
   x = 628,061.87/1,087.78
6. Step 6: Final answer
   x = 577.38