Finding the Fourth Proportional to 31,109, 42,931.10 and 16,961.90

Step by Step Solution

1. Step 1: Write the proportion equation
   31,109 : 42,931.10 = 16,961.90 : x
2. Step 2: Convert to fraction form
   31,109/42,931.10 = 16,961.90/x
3. Step 3: Cross multiply
   31,109x = 42,931.10 × 16,961.90
4. Step 4: Simplify right side
   31,109x = 728,193,025.09
5. Step 5: Solve for x
   x = 728,193,025.09/31,109
6. Step 6: Final answer
   x = 23,407.79