Finding the Fourth Proportional to 31,138.15, 42,970.82 and 16,991.30

Step by Step Solution

1. Step 1: Write the proportion equation
   31,138.15 : 42,970.82 = 16,991.30 : x
2. Step 2: Convert to fraction form
   31,138.15/42,970.82 = 16,991.30/x
3. Step 3: Cross multiply
   31,138.15x = 42,970.82 × 16,991.30
4. Step 4: Simplify right side
   31,138.15x = 730,130,008.91
5. Step 5: Solve for x
   x = 730,130,008.91/31,138.15
6. Step 6: Final answer
   x = 23,448.09