Finding the Third Proportional to 288.56 and 427.78

Step by Step Solution

1. Step 1: Write the proportion equation
   288.56 : 427.78 = 427.78 : x
2. Step 2: Convert to fraction form
   288.56/427.78 = 427.78/x
3. Step 3: Cross multiply
   288.56x = 427.78 × 427.78
4. Step 4: Simplify right side
   288.56x = 182,996.80
5. Step 5: Solve for x
   x = 182,996.80/288.56
6. Step 6: Final answer
   x = 634.17