Finding the Fourth Proportional to 20,870.02, 31,304.22 and 8,386.30

Step by Step Solution

1. Step 1: Write the proportion equation
   20,870.02 : 31,304.22 = 8,386.30 : x
2. Step 2: Convert to fraction form
   20,870.02/31,304.22 = 8,386.30/x
3. Step 3: Cross multiply
   20,870.02x = 31,304.22 × 8,386.30
4. Step 4: Simplify right side
   20,870.02x = 262,526,580.19
5. Step 5: Solve for x
   x = 262,526,580.19/20,870.02
6. Step 6: Final answer
   x = 12,579.12