Finding the Third Proportional to 288.56 and 680.91

Step by Step Solution

1. Step 1: Write the proportion equation
   288.56 : 680.91 = 680.91 : x
2. Step 2: Convert to fraction form
   288.56/680.91 = 680.91/x
3. Step 3: Cross multiply
   288.56x = 680.91 × 680.91
4. Step 4: Simplify right side
   288.56x = 463,633.32
5. Step 5: Solve for x
   x = 463,633.32/288.56
6. Step 6: Final answer
   x = 1,606.70