Finding the Fourth Proportional to 7,311.05, 10,002.79 and 7,280.07

Step by Step Solution

1. Step 1: Write the proportion equation
   7,311.05 : 10,002.79 = 7,280.07 : x
2. Step 2: Convert to fraction form
   7,311.05/10,002.79 = 7,280.07/x
3. Step 3: Cross multiply
   7,311.05x = 10,002.79 × 7,280.07
4. Step 4: Simplify right side
   7,311.05x = 72,821,011.40
5. Step 5: Solve for x
   x = 72,821,011.40/7,311.05
6. Step 6: Final answer
   x = 9,960.40