Finding the Third Proportional to 76.50 and 139.88

Step by Step Solution

1. Step 1: Write the proportion equation
   76.50 : 139.88 = 139.88 : x
2. Step 2: Convert to fraction form
   76.50/139.88 = 139.88/x
3. Step 3: Cross multiply
   76.50x = 139.88 × 139.88
4. Step 4: Simplify right side
   76.50x = 19,565.02
5. Step 5: Solve for x
   x = 19,565.02/76.50
6. Step 6: Final answer
   x = 255.75