Finding the Third Proportional to 142.59 and 310.78

Step by Step Solution

1. Step 1: Write the proportion equation
   142.59 : 310.78 = 310.78 : x
2. Step 2: Convert to fraction form
   142.59/310.78 = 310.78/x
3. Step 3: Cross multiply
   142.59x = 310.78 × 310.78
4. Step 4: Simplify right side
   142.59x = 96,584.99
5. Step 5: Solve for x
   x = 96,584.99/142.59
6. Step 6: Final answer
   x = 677.34