Finding the Third Proportional to 572.91 and 861.89

Step by Step Solution

1. Step 1: Write the proportion equation
   572.91 : 861.89 = 861.89 : x
2. Step 2: Convert to fraction form
   572.91/861.89 = 861.89/x
3. Step 3: Cross multiply
   572.91x = 861.89 × 861.89
4. Step 4: Simplify right side
   572.91x = 742,855.45
5. Step 5: Solve for x
   x = 742,855.45/572.91
6. Step 6: Final answer
   x = 1,296.64