Finding the Fourth Proportional to 11,989.62, 17,978.36 and 3,667.28

Step by Step Solution

1. Step 1: Write the proportion equation
   11,989.62 : 17,978.36 = 3,667.28 : x
2. Step 2: Convert to fraction form
   11,989.62/17,978.36 = 3,667.28/x
3. Step 3: Cross multiply
   11,989.62x = 17,978.36 × 3,667.28
4. Step 4: Simplify right side
   11,989.62x = 65,931,571.83
5. Step 5: Solve for x
   x = 65,931,571.83/11,989.62
6. Step 6: Final answer
   x = 5,499.05