Finding the Fourth Proportional to 7,111.62, 10,666.89 and 3,989.61

Step by Step Solution

1. Step 1: Write the proportion equation
   7,111.62 : 10,666.89 = 3,989.61 : x
2. Step 2: Convert to fraction form
   7,111.62/10,666.89 = 3,989.61/x
3. Step 3: Cross multiply
   7,111.62x = 10,666.89 × 3,989.61
4. Step 4: Simplify right side
   7,111.62x = 42,556,731.01
5. Step 5: Solve for x
   x = 42,556,731.01/7,111.62
6. Step 6: Final answer
   x = 5,984.11