Finding the Fourth Proportional to 8,335.52, 12,478.98 and 7,221.50

Step by Step Solution

1. Step 1: Write the proportion equation
   8,335.52 : 12,478.98 = 7,221.50 : x
2. Step 2: Convert to fraction form
   8,335.52/12,478.98 = 7,221.50/x
3. Step 3: Cross multiply
   8,335.52x = 12,478.98 × 7,221.50
4. Step 4: Simplify right side
   8,335.52x = 90,116,954.07
5. Step 5: Solve for x
   x = 90,116,954.07/8,335.52
6. Step 6: Final answer
   x = 10,811.20