Finding the Fourth Proportional to 20,648.80, 28,499.88 and 13,575.88

Step by Step Solution

1. Step 1: Write the proportion equation
   20,648.80 : 28,499.88 = 13,575.88 : x
2. Step 2: Convert to fraction form
   20,648.80/28,499.88 = 13,575.88/x
3. Step 3: Cross multiply
   20,648.80x = 28,499.88 × 13,575.88
4. Step 4: Simplify right side
   20,648.80x = 386,910,950.89
5. Step 5: Solve for x
   x = 386,910,950.89/20,648.80
6. Step 6: Final answer
   x = 18,737.70