Finding the Fourth Proportional to 3,978.64, 5,971.61 and 2,131.84

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.64 : 5,971.61 = 2,131.84 : x
2. Step 2: Convert to fraction form
   3,978.64/5,971.61 = 2,131.84/x
3. Step 3: Cross multiply
   3,978.64x = 5,971.61 × 2,131.84
4. Step 4: Simplify right side
   3,978.64x = 12,730,517.06
5. Step 5: Solve for x
   x = 12,730,517.06/3,978.64
6. Step 6: Final answer
   x = 3,199.72