Finding the Third Proportional to 487.69 and 1,264.78

Step by Step Solution

1. Step 1: Write the proportion equation
   487.69 : 1,264.78 = 1,264.78 : x
2. Step 2: Convert to fraction form
   487.69/1,264.78 = 1,264.78/x
3. Step 3: Cross multiply
   487.69x = 1,264.78 × 1,264.78
4. Step 4: Simplify right side
   487.69x = 1,599,671.61
5. Step 5: Solve for x
   x = 1,599,671.61/487.69
6. Step 6: Final answer
   x = 3,280.12