Finding the Fourth Proportional to 7,485.20, 10,329.64 and 4,128.15

Step by Step Solution

1. Step 1: Write the proportion equation
   7,485.20 : 10,329.64 = 4,128.15 : x
2. Step 2: Convert to fraction form
   7,485.20/10,329.64 = 4,128.15/x
3. Step 3: Cross multiply
   7,485.20x = 10,329.64 × 4,128.15
4. Step 4: Simplify right side
   7,485.20x = 42,642,303.37
5. Step 5: Solve for x
   x = 42,642,303.37/7,485.20
6. Step 6: Final answer
   x = 5,696.88