Finding the Third Proportional to 78.50 and 142.75

Step by Step Solution

1. Step 1: Write the proportion equation
   78.50 : 142.75 = 142.75 : x
2. Step 2: Convert to fraction form
   78.50/142.75 = 142.75/x
3. Step 3: Cross multiply
   78.50x = 142.75 × 142.75
4. Step 4: Simplify right side
   78.50x = 20,377.56
5. Step 5: Solve for x
   x = 20,377.56/78.50
6. Step 6: Final answer
   x = 259.59