Finding the Fourth Proportional to 20,722.32, 31,083.42 and 5,139.93

Step by Step Solution

1. Step 1: Write the proportion equation
   20,722.32 : 31,083.42 = 5,139.93 : x
2. Step 2: Convert to fraction form
   20,722.32/31,083.42 = 5,139.93/x
3. Step 3: Cross multiply
   20,722.32x = 31,083.42 × 5,139.93
4. Step 4: Simplify right side
   20,722.32x = 159,766,602.96
5. Step 5: Solve for x
   x = 159,766,602.96/20,722.32
6. Step 6: Final answer
   x = 7,709.88