Finding the Third Proportional to 309.50 and 672.50

Step by Step Solution

1. Step 1: Write the proportion equation
   309.50 : 672.50 = 672.50 : x
2. Step 2: Convert to fraction form
   309.50/672.50 = 672.50/x
3. Step 3: Cross multiply
   309.50x = 672.50 × 672.50
4. Step 4: Simplify right side
   309.50x = 452,256.25
5. Step 5: Solve for x
   x = 452,256.25/309.50
6. Step 6: Final answer
   x = 1,461.25