Finding the Third Proportional to 1,766.81 and 3,991.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,766.81 : 3,991.78 = 3,991.78 : x
2. Step 2: Convert to fraction form
   1,766.81/3,991.78 = 3,991.78/x
3. Step 3: Cross multiply
   1,766.81x = 3,991.78 × 3,991.78
4. Step 4: Simplify right side
   1,766.81x = 15,934,317.55
5. Step 5: Solve for x
   x = 15,934,317.55/1,766.81
6. Step 6: Final answer
   x = 9,018.68