Finding the Fourth Proportional to 80,155.71, 120,240.59 and 20,991.42

Step by Step Solution

1. Step 1: Write the proportion equation
   80,155.71 : 120,240.59 = 20,991.42 : x
2. Step 2: Convert to fraction form
   80,155.71/120,240.59 = 20,991.42/x
3. Step 3: Cross multiply
   80,155.71x = 120,240.59 × 20,991.42
4. Step 4: Simplify right side
   80,155.71x = 2,524,020,620.78
5. Step 5: Solve for x
   x = 2,524,020,620.78/80,155.71
6. Step 6: Final answer
   x = 31,488.97