Finding the Fourth Proportional to 28,216.16, 42,287.79 and 13,429.61

Step by Step Solution

1. Step 1: Write the proportion equation
   28,216.16 : 42,287.79 = 13,429.61 : x
2. Step 2: Convert to fraction form
   28,216.16/42,287.79 = 13,429.61/x
3. Step 3: Cross multiply
   28,216.16x = 42,287.79 × 13,429.61
4. Step 4: Simplify right side
   28,216.16x = 567,908,527.46
5. Step 5: Solve for x
   x = 567,908,527.46/28,216.16
6. Step 6: Final answer
   x = 20,127.07