Finding the Fourth Proportional to 5,111.82, 7,666.11 and 1,991.61

Step by Step Solution

1. Step 1: Write the proportion equation
   5,111.82 : 7,666.11 = 1,991.61 : x
2. Step 2: Convert to fraction form
   5,111.82/7,666.11 = 1,991.61/x
3. Step 3: Cross multiply
   5,111.82x = 7,666.11 × 1,991.61
4. Step 4: Simplify right side
   5,111.82x = 15,267,901.34
5. Step 5: Solve for x
   x = 15,267,901.34/5,111.82
6. Step 6: Final answer
   x = 2,986.78