Finding the Fourth Proportional to 15,778.89, 21,773.88 and 8,705.31

Step by Step Solution

1. Step 1: Write the proportion equation
   15,778.89 : 21,773.88 = 8,705.31 : x
2. Step 2: Convert to fraction form
   15,778.89/21,773.88 = 8,705.31/x
3. Step 3: Cross multiply
   15,778.89x = 21,773.88 × 8,705.31
4. Step 4: Simplify right side
   15,778.89x = 189,548,375.30
5. Step 5: Solve for x
   x = 189,548,375.30/15,778.89
6. Step 6: Final answer
   x = 12,012.78