Finding the Third Proportional to 3,990.94 and 8,699.06

Step by Step Solution

1. Step 1: Write the proportion equation
   3,990.94 : 8,699.06 = 8,699.06 : x
2. Step 2: Convert to fraction form
   3,990.94/8,699.06 = 8,699.06/x
3. Step 3: Cross multiply
   3,990.94x = 8,699.06 × 8,699.06
4. Step 4: Simplify right side
   3,990.94x = 75,673,688.38
5. Step 5: Solve for x
   x = 75,673,688.38/3,990.94
6. Step 6: Final answer
   x = 18,961.38