Finding the Fourth Proportional to 20,945.34, 31,409.82 and 7,790.55

Step by Step Solution

1. Step 1: Write the proportion equation
   20,945.34 : 31,409.82 = 7,790.55 : x
2. Step 2: Convert to fraction form
   20,945.34/31,409.82 = 7,790.55/x
3. Step 3: Cross multiply
   20,945.34x = 31,409.82 × 7,790.55
4. Step 4: Simplify right side
   20,945.34x = 244,699,773.20
5. Step 5: Solve for x
   x = 244,699,773.20/20,945.34
6. Step 6: Final answer
   x = 11,682.78