Finding the Third Proportional to 3,851.25 and 8,420.75

Step by Step Solution

1. Step 1: Write the proportion equation
   3,851.25 : 8,420.75 = 8,420.75 : x
2. Step 2: Convert to fraction form
   3,851.25/8,420.75 = 8,420.75/x
3. Step 3: Cross multiply
   3,851.25x = 8,420.75 × 8,420.75
4. Step 4: Simplify right side
   3,851.25x = 70,909,030.56
5. Step 5: Solve for x
   x = 70,909,030.56/3,851.25
6. Step 6: Final answer
   x = 18,411.95