Finding the Third Proportional to 420.56 and 561.56

Step by Step Solution

1. Step 1: Write the proportion equation
   420.56 : 561.56 = 561.56 : x
2. Step 2: Convert to fraction form
   420.56/561.56 = 561.56/x
3. Step 3: Cross multiply
   420.56x = 561.56 × 561.56
4. Step 4: Simplify right side
   420.56x = 315,352.44
5. Step 5: Solve for x
   x = 315,352.44/420.56
6. Step 6: Final answer
   x = 749.83