Finding the Fourth Proportional to 1,411.29, 2,115.86 and 641.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,411.29 : 2,115.86 = 641.25 : x
2. Step 2: Convert to fraction form
   1,411.29/2,115.86 = 641.25/x
3. Step 3: Cross multiply
   1,411.29x = 2,115.86 × 641.25
4. Step 4: Simplify right side
   1,411.29x = 1,356,792.02
5. Step 5: Solve for x
   x = 1,356,792.02/1,411.29
6. Step 6: Final answer
   x = 961.38