Finding the Third Proportional to 668 and 978.50

Step by Step Solution

1. Step 1: Write the proportion equation
   668 : 978.50 = 978.50 : x
2. Step 2: Convert to fraction form
   668/978.50 = 978.50/x
3. Step 3: Cross multiply
   668x = 978.50 × 978.50
4. Step 4: Simplify right side
   668x = 957,462.25
5. Step 5: Solve for x
   x = 957,462.25/668
6. Step 6: Final answer
   x = 1,433.33