Finding the Fourth Proportional to 31,066.80, 42,871.68 and 16,920

Step by Step Solution

1. Step 1: Write the proportion equation
   31,066.80 : 42,871.68 = 16,920 : x
2. Step 2: Convert to fraction form
   31,066.80/42,871.68 = 16,920/x
3. Step 3: Cross multiply
   31,066.80x = 42,871.68 × 16,920
4. Step 4: Simplify right side
   31,066.80x = 725,388,825.60
5. Step 5: Solve for x
   x = 725,388,825.60/31,066.80
6. Step 6: Final answer
   x = 23,349.33