Finding the Third Proportional to 781.31 and 1,728.56

Step by Step Solution

1. Step 1: Write the proportion equation
   781.31 : 1,728.56 = 1,728.56 : x
2. Step 2: Convert to fraction form
   781.31/1,728.56 = 1,728.56/x
3. Step 3: Cross multiply
   781.31x = 1,728.56 × 1,728.56
4. Step 4: Simplify right side
   781.31x = 2,987,928.32
5. Step 5: Solve for x
   x = 2,987,928.32/781.31
6. Step 6: Final answer
   x = 3,824.24