Finding the Third Proportional to 746.40 and 1,128.78

Step by Step Solution

1. Step 1: Write the proportion equation
   746.40 : 1,128.78 = 1,128.78 : x
2. Step 2: Convert to fraction form
   746.40/1,128.78 = 1,128.78/x
3. Step 3: Cross multiply
   746.40x = 1,128.78 × 1,128.78
4. Step 4: Simplify right side
   746.40x = 1,274,142.70
5. Step 5: Solve for x
   x = 1,274,142.70/746.40
6. Step 6: Final answer
   x = 1,707.05