Finding the Fourth Proportional to 1,387.78, 1,914.38 and 889.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.78 : 1,914.38 = 889.87 : x
2. Step 2: Convert to fraction form
   1,387.78/1,914.38 = 889.87/x
3. Step 3: Cross multiply
   1,387.78x = 1,914.38 × 889.87
4. Step 4: Simplify right side
   1,387.78x = 1,703,552.03
5. Step 5: Solve for x
   x = 1,703,552.03/1,387.78
6. Step 6: Final answer
   x = 1,227.53