Finding the Third Proportional to 621.50 and 931.50

Step by Step Solution

1. Step 1: Write the proportion equation
   621.50 : 931.50 = 931.50 : x
2. Step 2: Convert to fraction form
   621.50/931.50 = 931.50/x
3. Step 3: Cross multiply
   621.50x = 931.50 × 931.50
4. Step 4: Simplify right side
   621.50x = 867,692.25
5. Step 5: Solve for x
   x = 867,692.25/621.50
6. Step 6: Final answer
   x = 1,396.13