Finding the Fourth Proportional to 19,128.24, 28,658.76 and 13,288.56

Step by Step Solution

1. Step 1: Write the proportion equation
   19,128.24 : 28,658.76 = 13,288.56 : x
2. Step 2: Convert to fraction form
   19,128.24/28,658.76 = 13,288.56/x
3. Step 3: Cross multiply
   19,128.24x = 28,658.76 × 13,288.56
4. Step 4: Simplify right side
   19,128.24x = 380,833,651.79
5. Step 5: Solve for x
   x = 380,833,651.79/19,128.24
6. Step 6: Final answer
   x = 19,909.50