Finding the Fourth Proportional to 30,969.55, 42,755.72 and 20,389.94

Step by Step Solution

1. Step 1: Write the proportion equation
   30,969.55 : 42,755.72 = 20,389.94 : x
2. Step 2: Convert to fraction form
   30,969.55/42,755.72 = 20,389.94/x
3. Step 3: Cross multiply
   30,969.55x = 42,755.72 × 20,389.94
4. Step 4: Simplify right side
   30,969.55x = 871,786,565.46
5. Step 5: Solve for x
   x = 871,786,565.46/30,969.55
6. Step 6: Final answer
   x = 28,149.80