Finding the Fourth Proportional to 1,389.53, 1,916.38 and 1,078.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.53 : 1,916.38 = 1,078.49 : x
2. Step 2: Convert to fraction form
   1,389.53/1,916.38 = 1,078.49/x
3. Step 3: Cross multiply
   1,389.53x = 1,916.38 × 1,078.49
4. Step 4: Simplify right side
   1,389.53x = 2,066,796.67
5. Step 5: Solve for x
   x = 2,066,796.67/1,389.53
6. Step 6: Final answer
   x = 1,487.41