Finding the Third Proportional to 3,991.50 and 8,487.75

Step by Step Solution

1. Step 1: Write the proportion equation
   3,991.50 : 8,487.75 = 8,487.75 : x
2. Step 2: Convert to fraction form
   3,991.50/8,487.75 = 8,487.75/x
3. Step 3: Cross multiply
   3,991.50x = 8,487.75 × 8,487.75
4. Step 4: Simplify right side
   3,991.50x = 72,041,900.06
5. Step 5: Solve for x
   x = 72,041,900.06/3,991.50
6. Step 6: Final answer
   x = 18,048.83