Finding the Third Proportional to 665.72 and 1,070.30

Step by Step Solution

1. Step 1: Write the proportion equation
   665.72 : 1,070.30 = 1,070.30 : x
2. Step 2: Convert to fraction form
   665.72/1,070.30 = 1,070.30/x
3. Step 3: Cross multiply
   665.72x = 1,070.30 × 1,070.30
4. Step 4: Simplify right side
   665.72x = 1,145,535.40
5. Step 5: Solve for x
   x = 1,145,535.40/665.72
6. Step 6: Final answer
   x = 1,720.75