Finding the Third Proportional to 148.59 and 319.31

Step by Step Solution

1. Step 1: Write the proportion equation
   148.59 : 319.31 = 319.31 : x
2. Step 2: Convert to fraction form
   148.59/319.31 = 319.31/x
3. Step 3: Cross multiply
   148.59x = 319.31 × 319.31
4. Step 4: Simplify right side
   148.59x = 101,960.47
5. Step 5: Solve for x
   x = 101,960.47/148.59
6. Step 6: Final answer
   x = 686.17