Finding the Fourth Proportional to 10,078.50, 15,085.40 and 5,386.78

Step by Step Solution

1. Step 1: Write the proportion equation
   10,078.50 : 15,085.40 = 5,386.78 : x
2. Step 2: Convert to fraction form
   10,078.50/15,085.40 = 5,386.78/x
3. Step 3: Cross multiply
   10,078.50x = 15,085.40 × 5,386.78
4. Step 4: Simplify right side
   10,078.50x = 81,261,731.01
5. Step 5: Solve for x
   x = 81,261,731.01/10,078.50
6. Step 6: Final answer
   x = 8,062.88