Finding the Fourth Proportional to 9,419.90, 12,999.35 and 5,228.15

Step by Step Solution

1. Step 1: Write the proportion equation
   9,419.90 : 12,999.35 = 5,228.15 : x
2. Step 2: Convert to fraction form
   9,419.90/12,999.35 = 5,228.15/x
3. Step 3: Cross multiply
   9,419.90x = 12,999.35 × 5,228.15
4. Step 4: Simplify right side
   9,419.90x = 67,962,499.78
5. Step 5: Solve for x
   x = 67,962,499.78/9,419.90
6. Step 6: Final answer
   x = 7,214.78