Finding the Fourth Proportional to 20,724.93, 31,087.71 and 5,142.57

Step by Step Solution

1. Step 1: Write the proportion equation
   20,724.93 : 31,087.71 = 5,142.57 : x
2. Step 2: Convert to fraction form
   20,724.93/31,087.71 = 5,142.57/x
3. Step 3: Cross multiply
   20,724.93x = 31,087.71 × 5,142.57
4. Step 4: Simplify right side
   20,724.93x = 159,870,724.81
5. Step 5: Solve for x
   x = 159,870,724.81/20,724.93
6. Step 6: Final answer
   x = 7,713.93