Finding the Fourth Proportional to 31,138.25, 42,970.16 and 16,991.33

Step by Step Solution

1. Step 1: Write the proportion equation
   31,138.25 : 42,970.16 = 16,991.33 : x
2. Step 2: Convert to fraction form
   31,138.25/42,970.16 = 16,991.33/x
3. Step 3: Cross multiply
   31,138.25x = 42,970.16 × 16,991.33
4. Step 4: Simplify right side
   31,138.25x = 730,119,996.34
5. Step 5: Solve for x
   x = 730,119,996.34/31,138.25
6. Step 6: Final answer
   x = 23,447.69