Finding the Fourth Proportional to 11,983.74, 17,978.55 and 3,663.90

Step by Step Solution

1. Step 1: Write the proportion equation
   11,983.74 : 17,978.55 = 3,663.90 : x
2. Step 2: Convert to fraction form
   11,983.74/17,978.55 = 3,663.90/x
3. Step 3: Cross multiply
   11,983.74x = 17,978.55 × 3,663.90
4. Step 4: Simplify right side
   11,983.74x = 65,871,609.35
5. Step 5: Solve for x
   x = 65,871,609.35/11,983.74
6. Step 6: Final answer
   x = 5,496.75