Finding the Fourth Proportional to 10,056.48, 15,080.16 and 5,128.80

Step by Step Solution

1. Step 1: Write the proportion equation
   10,056.48 : 15,080.16 = 5,128.80 : x
2. Step 2: Convert to fraction form
   10,056.48/15,080.16 = 5,128.80/x
3. Step 3: Cross multiply
   10,056.48x = 15,080.16 × 5,128.80
4. Step 4: Simplify right side
   10,056.48x = 77,343,124.61
5. Step 5: Solve for x
   x = 77,343,124.61/10,056.48
6. Step 6: Final answer
   x = 7,690.87