Finding the Fourth Proportional to 5,406.16, 8,111.76 and 5,318.80

Step by Step Solution

1. Step 1: Write the proportion equation
   5,406.16 : 8,111.76 = 5,318.80 : x
2. Step 2: Convert to fraction form
   5,406.16/8,111.76 = 5,318.80/x
3. Step 3: Cross multiply
   5,406.16x = 8,111.76 × 5,318.80
4. Step 4: Simplify right side
   5,406.16x = 43,144,829.09
5. Step 5: Solve for x
   x = 43,144,829.09/5,406.16
6. Step 6: Final answer
   x = 7,980.68