Finding the Fourth Proportional to 9,621.12, 13,275.36 and 5,428.56

Step by Step Solution

1. Step 1: Write the proportion equation
   9,621.12 : 13,275.36 = 5,428.56 : x
2. Step 2: Convert to fraction form
   9,621.12/13,275.36 = 5,428.56/x
3. Step 3: Cross multiply
   9,621.12x = 13,275.36 × 5,428.56
4. Step 4: Simplify right side
   9,621.12x = 72,066,088.28
5. Step 5: Solve for x
   x = 72,066,088.28/9,621.12
6. Step 6: Final answer
   x = 7,490.41