Finding the Fourth Proportional to 9,415.89, 12,992.58 and 5,638.16

Step by Step Solution

1. Step 1: Write the proportion equation
   9,415.89 : 12,992.58 = 5,638.16 : x
2. Step 2: Convert to fraction form
   9,415.89/12,992.58 = 5,638.16/x
3. Step 3: Cross multiply
   9,415.89x = 12,992.58 × 5,638.16
4. Step 4: Simplify right side
   9,415.89x = 73,254,277.33
5. Step 5: Solve for x
   x = 73,254,277.33/9,415.89
6. Step 6: Final answer
   x = 7,779.86