Finding the Third Proportional to 3,910.78 and 8,489.81

Step by Step Solution

1. Step 1: Write the proportion equation
   3,910.78 : 8,489.81 = 8,489.81 : x
2. Step 2: Convert to fraction form
   3,910.78/8,489.81 = 8,489.81/x
3. Step 3: Cross multiply
   3,910.78x = 8,489.81 × 8,489.81
4. Step 4: Simplify right side
   3,910.78x = 72,076,916.29
5. Step 5: Solve for x
   x = 72,076,916.29/3,910.78
6. Step 6: Final answer
   x = 18,430.31