Finding the Fourth Proportional to 10,489.85, 15,728.48 and 7,116.78

Step by Step Solution

1. Step 1: Write the proportion equation
   10,489.85 : 15,728.48 = 7,116.78 : x
2. Step 2: Convert to fraction form
   10,489.85/15,728.48 = 7,116.78/x
3. Step 3: Cross multiply
   10,489.85x = 15,728.48 × 7,116.78
4. Step 4: Simplify right side
   10,489.85x = 111,936,096.31
5. Step 5: Solve for x
   x = 111,936,096.31/10,489.85
6. Step 6: Final answer
   x = 10,670.90