Finding the Fourth Proportional to 3,870.61, 5,805.90 and 1,405.42

Step by Step Solution

1. Step 1: Write the proportion equation
   3,870.61 : 5,805.90 = 1,405.42 : x
2. Step 2: Convert to fraction form
   3,870.61/5,805.90 = 1,405.42/x
3. Step 3: Cross multiply
   3,870.61x = 5,805.90 × 1,405.42
4. Step 4: Simplify right side
   3,870.61x = 8,159,727.98
5. Step 5: Solve for x
   x = 8,159,727.98/3,870.61
6. Step 6: Final answer
   x = 2,108.12