Finding the Third Proportional to 142.31 and 312.33

Step by Step Solution

1. Step 1: Write the proportion equation
   142.31 : 312.33 = 312.33 : x
2. Step 2: Convert to fraction form
   142.31/312.33 = 312.33/x
3. Step 3: Cross multiply
   142.31x = 312.33 × 312.33
4. Step 4: Simplify right side
   142.31x = 97,548.86
5. Step 5: Solve for x
   x = 97,548.86/142.31
6. Step 6: Final answer
   x = 685.46