Finding the Fourth Proportional to 81,081.72, 121,616.58 and 28,491.72

Step by Step Solution

1. Step 1: Write the proportion equation
   81,081.72 : 121,616.58 = 28,491.72 : x
2. Step 2: Convert to fraction form
   81,081.72/121,616.58 = 28,491.72/x
3. Step 3: Cross multiply
   81,081.72x = 121,616.58 × 28,491.72
4. Step 4: Simplify right side
   81,081.72x = 3,465,065,544.72
5. Step 5: Solve for x
   x = 3,465,065,544.72/81,081.72
6. Step 6: Final answer
   x = 42,735.47