Finding the Fourth Proportional to 31,139.14, 42,971.61 and 16,991.74

Step by Step Solution

1. Step 1: Write the proportion equation
   31,139.14 : 42,971.61 = 16,991.74 : x
2. Step 2: Convert to fraction form
   31,139.14/42,971.61 = 16,991.74/x
3. Step 3: Cross multiply
   31,139.14x = 42,971.61 × 16,991.74
4. Step 4: Simplify right side
   31,139.14x = 730,162,424.50
5. Step 5: Solve for x
   x = 730,162,424.50/31,139.14
6. Step 6: Final answer
   x = 23,448.38