Finding the Fourth Proportional to 13,870.31, 20,804.85 and 3,875.12

Step by Step Solution

1. Step 1: Write the proportion equation
   13,870.31 : 20,804.85 = 3,875.12 : x
2. Step 2: Convert to fraction form
   13,870.31/20,804.85 = 3,875.12/x
3. Step 3: Cross multiply
   13,870.31x = 20,804.85 × 3,875.12
4. Step 4: Simplify right side
   13,870.31x = 80,621,290.33
5. Step 5: Solve for x
   x = 80,621,290.33/13,870.31
6. Step 6: Final answer
   x = 5,812.51