Finding the Third Proportional to 421.50 and 808.50

Step by Step Solution

1. Step 1: Write the proportion equation
   421.50 : 808.50 = 808.50 : x
2. Step 2: Convert to fraction form
   421.50/808.50 = 808.50/x
3. Step 3: Cross multiply
   421.50x = 808.50 × 808.50
4. Step 4: Simplify right side
   421.50x = 653,672.25
5. Step 5: Solve for x
   x = 653,672.25/421.50
6. Step 6: Final answer
   x = 1,550.82