Finding the Fourth Proportional to 8,991.85, 12,416.59 and 5,640.43

Step by Step Solution

1. Step 1: Write the proportion equation
   8,991.85 : 12,416.59 = 5,640.43 : x
2. Step 2: Convert to fraction form
   8,991.85/12,416.59 = 5,640.43/x
3. Step 3: Cross multiply
   8,991.85x = 12,416.59 × 5,640.43
4. Step 4: Simplify right side
   8,991.85x = 70,034,871.10
5. Step 5: Solve for x
   x = 70,034,871.10/8,991.85
6. Step 6: Final answer
   x = 7,788.70