Finding the Fourth Proportional to 9,399.10, 12,970.83 and 5,420.11

Step by Step Solution

1. Step 1: Write the proportion equation
   9,399.10 : 12,970.83 = 5,420.11 : x
2. Step 2: Convert to fraction form
   9,399.10/12,970.83 = 5,420.11/x
3. Step 3: Cross multiply
   9,399.10x = 12,970.83 × 5,420.11
4. Step 4: Simplify right side
   9,399.10x = 70,303,325.39
5. Step 5: Solve for x
   x = 70,303,325.39/9,399.10
6. Step 6: Final answer
   x = 7,479.79