Finding the Fourth Proportional to 3,940.64, 5,426.88 and 3,928.76

Step by Step Solution

1. Step 1: Write the proportion equation
   3,940.64 : 5,426.88 = 3,928.76 : x
2. Step 2: Convert to fraction form
   3,940.64/5,426.88 = 3,928.76/x
3. Step 3: Cross multiply
   3,940.64x = 5,426.88 × 3,928.76
4. Step 4: Simplify right side
   3,940.64x = 21,320,909.07
5. Step 5: Solve for x
   x = 21,320,909.07/3,940.64
6. Step 6: Final answer
   x = 5,410.52