Finding the Fourth Proportional to 12,780.10, 17,631.34 and 8,061.63

Step by Step Solution

1. Step 1: Write the proportion equation
   12,780.10 : 17,631.34 = 8,061.63 : x
2. Step 2: Convert to fraction form
   12,780.10/17,631.34 = 8,061.63/x
3. Step 3: Cross multiply
   12,780.10x = 17,631.34 × 8,061.63
4. Step 4: Simplify right side
   12,780.10x = 142,137,339.48
5. Step 5: Solve for x
   x = 142,137,339.48/12,780.10
6. Step 6: Final answer
   x = 11,121.77