Finding the Fourth Proportional to 5,642.37, 7,784.10 and 3,870.90

Step by Step Solution

1. Step 1: Write the proportion equation
   5,642.37 : 7,784.10 = 3,870.90 : x
2. Step 2: Convert to fraction form
   5,642.37/7,784.10 = 3,870.90/x
3. Step 3: Cross multiply
   5,642.37x = 7,784.10 × 3,870.90
4. Step 4: Simplify right side
   5,642.37x = 30,131,472.69
5. Step 5: Solve for x
   x = 30,131,472.69/5,642.37
6. Step 6: Final answer
   x = 5,340.22