Finding the Fourth Proportional to 8,667.72, 12,991.50 and 5,549.40

Step by Step Solution

1. Step 1: Write the proportion equation
   8,667.72 : 12,991.50 = 5,549.40 : x
2. Step 2: Convert to fraction form
   8,667.72/12,991.50 = 5,549.40/x
3. Step 3: Cross multiply
   8,667.72x = 12,991.50 × 5,549.40
4. Step 4: Simplify right side
   8,667.72x = 72,095,030.10
5. Step 5: Solve for x
   x = 72,095,030.10/8,667.72
6. Step 6: Final answer
   x = 8,317.65