Finding the Third Proportional to 211.50 and 425.50

Step by Step Solution

1. Step 1: Write the proportion equation
   211.50 : 425.50 = 425.50 : x
2. Step 2: Convert to fraction form
   211.50/425.50 = 425.50/x
3. Step 3: Cross multiply
   211.50x = 425.50 × 425.50
4. Step 4: Simplify right side
   211.50x = 181,050.25
5. Step 5: Solve for x
   x = 181,050.25/211.50
6. Step 6: Final answer
   x = 856.03