Finding the Third Proportional to 685.50 and 1,507.50

Step by Step Solution

1. Step 1: Write the proportion equation
   685.50 : 1,507.50 = 1,507.50 : x
2. Step 2: Convert to fraction form
   685.50/1,507.50 = 1,507.50/x
3. Step 3: Cross multiply
   685.50x = 1,507.50 × 1,507.50
4. Step 4: Simplify right side
   685.50x = 2,272,556.25
5. Step 5: Solve for x
   x = 2,272,556.25/685.50
6. Step 6: Final answer
   x = 3,315.18