Finding the Fourth Proportional to 13,987.50, 20,978.03 and 3,992.06

Step by Step Solution

1. Step 1: Write the proportion equation
   13,987.50 : 20,978.03 = 3,992.06 : x
2. Step 2: Convert to fraction form
   13,987.50/20,978.03 = 3,992.06/x
3. Step 3: Cross multiply
   13,987.50x = 20,978.03 × 3,992.06
4. Step 4: Simplify right side
   13,987.50x = 83,745,429.59
5. Step 5: Solve for x
   x = 83,745,429.59/13,987.50
6. Step 6: Final answer
   x = 5,987.16