Finding the Third Proportional to 420 and 650.50

Step by Step Solution

1. Step 1: Write the proportion equation
   420 : 650.50 = 650.50 : x
2. Step 2: Convert to fraction form
   420/650.50 = 650.50/x
3. Step 3: Cross multiply
   420x = 650.50 × 650.50
4. Step 4: Simplify right side
   420x = 423,150.25
5. Step 5: Solve for x
   x = 423,150.25/420
6. Step 6: Final answer
   x = 1,007.50