Finding the Fourth Proportional to 13,218.48, 19,835.55 and 5,321.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,218.48 : 19,835.55 = 5,321.72 : x
2. Step 2: Convert to fraction form
   13,218.48/19,835.55 = 5,321.72/x
3. Step 3: Cross multiply
   13,218.48x = 19,835.55 × 5,321.72
4. Step 4: Simplify right side
   13,218.48x = 105,559,292.73
5. Step 5: Solve for x
   x = 105,559,292.73/13,218.48
6. Step 6: Final answer
   x = 7,985.74