Finding the Fourth Proportional to 9,990.21, 13,786.54 and 5,513.97

Step by Step Solution

1. Step 1: Write the proportion equation
   9,990.21 : 13,786.54 = 5,513.97 : x
2. Step 2: Convert to fraction form
   9,990.21/13,786.54 = 5,513.97/x
3. Step 3: Cross multiply
   9,990.21x = 13,786.54 × 5,513.97
4. Step 4: Simplify right side
   9,990.21x = 76,018,567.96
5. Step 5: Solve for x
   x = 76,018,567.96/9,990.21
6. Step 6: Final answer
   x = 7,609.31