Finding the Third Proportional to 485.72 and 772.45

Step by Step Solution

1. Step 1: Write the proportion equation
   485.72 : 772.45 = 772.45 : x
2. Step 2: Convert to fraction form
   485.72/772.45 = 772.45/x
3. Step 3: Cross multiply
   485.72x = 772.45 × 772.45
4. Step 4: Simplify right side
   485.72x = 596,683.83
5. Step 5: Solve for x
   x = 596,683.83/485.72
6. Step 6: Final answer
   x = 1,228.46