Finding the Fourth Proportional to 9,991.71, 13,788.48 and 5,515.46

Step by Step Solution

1. Step 1: Write the proportion equation
   9,991.71 : 13,788.48 = 5,515.46 : x
2. Step 2: Convert to fraction form
   9,991.71/13,788.48 = 5,515.46/x
3. Step 3: Cross multiply
   9,991.71x = 13,788.48 × 5,515.46
4. Step 4: Simplify right side
   9,991.71x = 76,049,890.91
5. Step 5: Solve for x
   x = 76,049,890.91/9,991.71
6. Step 6: Final answer
   x = 7,611.30