Finding the Fourth Proportional to 7,911.15, 10,915.20 and 5,518.55

Step by Step Solution

1. Step 1: Write the proportion equation
   7,911.15 : 10,915.20 = 5,518.55 : x
2. Step 2: Convert to fraction form
   7,911.15/10,915.20 = 5,518.55/x
3. Step 3: Cross multiply
   7,911.15x = 10,915.20 × 5,518.55
4. Step 4: Simplify right side
   7,911.15x = 60,236,022.38
5. Step 5: Solve for x
   x = 60,236,022.38/7,911.15
6. Step 6: Final answer
   x = 7,614.07