Finding the Fourth Proportional to 9,415.08, 12,992.90 and 5,223.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,415.08 : 12,992.90 = 5,223.72 : x
2. Step 2: Convert to fraction form
   9,415.08/12,992.90 = 5,223.72/x
3. Step 3: Cross multiply
   9,415.08x = 12,992.90 × 5,223.72
4. Step 4: Simplify right side
   9,415.08x = 67,871,271.59
5. Step 5: Solve for x
   x = 67,871,271.59/9,415.08
6. Step 6: Final answer
   x = 7,208.78