Finding the Fourth Proportional to 6,389.17, 8,815.60 and 3,870.17

Step by Step Solution

1. Step 1: Write the proportion equation
   6,389.17 : 8,815.60 = 3,870.17 : x
2. Step 2: Convert to fraction form
   6,389.17/8,815.60 = 3,870.17/x
3. Step 3: Cross multiply
   6,389.17x = 8,815.60 × 3,870.17
4. Step 4: Simplify right side
   6,389.17x = 34,117,870.65
5. Step 5: Solve for x
   x = 34,117,870.65/6,389.17
6. Step 6: Final answer
   x = 5,339.95