Finding the Fourth Proportional to 1,039.89, 1,558.64 and 389.97

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.89 : 1,558.64 = 389.97 : x
2. Step 2: Convert to fraction form
   1,039.89/1,558.64 = 389.97/x
3. Step 3: Cross multiply
   1,039.89x = 1,558.64 × 389.97
4. Step 4: Simplify right side
   1,039.89x = 607,820.89
5. Step 5: Solve for x
   x = 607,820.89/1,039.89
6. Step 6: Final answer
   x = 584.50