Finding the Fourth Proportional to 1,389.35, 2,086.10 and 872.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.35 : 2,086.10 = 872.62 : x
2. Step 2: Convert to fraction form
   1,389.35/2,086.10 = 872.62/x
3. Step 3: Cross multiply
   1,389.35x = 2,086.10 × 872.62
4. Step 4: Simplify right side
   1,389.35x = 1,820,382.92
5. Step 5: Solve for x
   x = 1,820,382.92/1,389.35
6. Step 6: Final answer
   x = 1,310.24