Finding the Fourth Proportional to 9,920.04, 13,687.24 and 5,728.28

Step by Step Solution

1. Step 1: Write the proportion equation
   9,920.04 : 13,687.24 = 5,728.28 : x
2. Step 2: Convert to fraction form
   9,920.04/13,687.24 = 5,728.28/x
3. Step 3: Cross multiply
   9,920.04x = 13,687.24 × 5,728.28
4. Step 4: Simplify right side
   9,920.04x = 78,404,343.15
5. Step 5: Solve for x
   x = 78,404,343.15/9,920.04
6. Step 6: Final answer
   x = 7,903.63