Finding the Third Proportional to 123.38 and 256.63

Step by Step Solution

1. Step 1: Write the proportion equation
   123.38 : 256.63 = 256.63 : x
2. Step 2: Convert to fraction form
   123.38/256.63 = 256.63/x
3. Step 3: Cross multiply
   123.38x = 256.63 × 256.63
4. Step 4: Simplify right side
   123.38x = 65,856.39
5. Step 5: Solve for x
   x = 65,856.39/123.38
6. Step 6: Final answer
   x = 533.79