Finding the Fourth Proportional to 28,085.11, 42,140.69 and 12,288.06

Step by Step Solution

1. Step 1: Write the proportion equation
   28,085.11 : 42,140.69 = 12,288.06 : x
2. Step 2: Convert to fraction form
   28,085.11/42,140.69 = 12,288.06/x
3. Step 3: Cross multiply
   28,085.11x = 42,140.69 × 12,288.06
4. Step 4: Simplify right side
   28,085.11x = 517,827,265.72
5. Step 5: Solve for x
   x = 517,827,265.72/28,085.11
6. Step 6: Final answer
   x = 18,437.79