Finding the Third Proportional to 642 and 1,401.75

Step by Step Solution

1. Step 1: Write the proportion equation
   642 : 1,401.75 = 1,401.75 : x
2. Step 2: Convert to fraction form
   642/1,401.75 = 1,401.75/x
3. Step 3: Cross multiply
   642x = 1,401.75 × 1,401.75
4. Step 4: Simplify right side
   642x = 1,964,903.06
5. Step 5: Solve for x
   x = 1,964,903.06/642
6. Step 6: Final answer
   x = 3,060.60