Finding the Fourth Proportional to 7,871.62, 11,814.72 and 3,978.76

Step by Step Solution

1. Step 1: Write the proportion equation
   7,871.62 : 11,814.72 = 3,978.76 : x
2. Step 2: Convert to fraction form
   7,871.62/11,814.72 = 3,978.76/x
3. Step 3: Cross multiply
   7,871.62x = 11,814.72 × 3,978.76
4. Step 4: Simplify right side
   7,871.62x = 47,007,935.35
5. Step 5: Solve for x
   x = 47,007,935.35/7,871.62
6. Step 6: Final answer
   x = 5,971.82