Finding the Third Proportional to 491.91 and 558.56

Step by Step Solution

1. Step 1: Write the proportion equation
   491.91 : 558.56 = 558.56 : x
2. Step 2: Convert to fraction form
   491.91/558.56 = 558.56/x
3. Step 3: Cross multiply
   491.91x = 558.56 × 558.56
4. Step 4: Simplify right side
   491.91x = 311,992.07
5. Step 5: Solve for x
   x = 311,992.07/491.91
6. Step 6: Final answer
   x = 634.25