Finding the Fourth Proportional to 8,996.91, 12,407.69 and 5,640.09

Step by Step Solution

1. Step 1: Write the proportion equation
   8,996.91 : 12,407.69 = 5,640.09 : x
2. Step 2: Convert to fraction form
   8,996.91/12,407.69 = 5,640.09/x
3. Step 3: Cross multiply
   8,996.91x = 12,407.69 × 5,640.09
4. Step 4: Simplify right side
   8,996.91x = 69,980,460.09
5. Step 5: Solve for x
   x = 69,980,460.09/8,996.91
6. Step 6: Final answer
   x = 7,778.28