Finding the Fourth Proportional to 9,991.87, 13,785.72 and 5,799.31

Step by Step Solution

1. Step 1: Write the proportion equation
   9,991.87 : 13,785.72 = 5,799.31 : x
2. Step 2: Convert to fraction form
   9,991.87/13,785.72 = 5,799.31/x
3. Step 3: Cross multiply
   9,991.87x = 13,785.72 × 5,799.31
4. Step 4: Simplify right side
   9,991.87x = 79,947,663.85
5. Step 5: Solve for x
   x = 79,947,663.85/9,991.87
6. Step 6: Final answer
   x = 8,001.27