Finding the Fourth Proportional to 9,369.88, 12,931.92 and 5,390.21

Step by Step Solution

1. Step 1: Write the proportion equation
   9,369.88 : 12,931.92 = 5,390.21 : x
2. Step 2: Convert to fraction form
   9,369.88/12,931.92 = 5,390.21/x
3. Step 3: Cross multiply
   9,369.88x = 12,931.92 × 5,390.21
4. Step 4: Simplify right side
   9,369.88x = 69,705,796.83
5. Step 5: Solve for x
   x = 69,705,796.83/9,369.88
6. Step 6: Final answer
   x = 7,439.35