Finding the Fourth Proportional to 31,131.68, 42,961.56 and 16,985.12

Step by Step Solution

1. Step 1: Write the proportion equation
   31,131.68 : 42,961.56 = 16,985.12 : x
2. Step 2: Convert to fraction form
   31,131.68/42,961.56 = 16,985.12/x
3. Step 3: Cross multiply
   31,131.68x = 42,961.56 × 16,985.12
4. Step 4: Simplify right side
   31,131.68x = 729,707,251.99
5. Step 5: Solve for x
   x = 729,707,251.99/31,131.68
6. Step 6: Final answer
   x = 23,439.38