Finding the Third Proportional to 686 and 931.50

Step by Step Solution

1. Step 1: Write the proportion equation
   686 : 931.50 = 931.50 : x
2. Step 2: Convert to fraction form
   686/931.50 = 931.50/x
3. Step 3: Cross multiply
   686x = 931.50 × 931.50
4. Step 4: Simplify right side
   686x = 867,692.25
5. Step 5: Solve for x
   x = 867,692.25/686
6. Step 6: Final answer
   x = 1,264.86