Finding the Third Proportional to 688.50 and 1,020

Step by Step Solution

1. Step 1: Write the proportion equation
   688.50 : 1,020 = 1,020 : x
2. Step 2: Convert to fraction form
   688.50/1,020 = 1,020/x
3. Step 3: Cross multiply
   688.50x = 1,020 × 1,020
4. Step 4: Simplify right side
   688.50x = 1,040,400
5. Step 5: Solve for x
   x = 1,040,400/688.50
6. Step 6: Final answer
   x = 1,511.11