Finding the Third Proportional to 70.77 and 139.61

Step by Step Solution

1. Step 1: Write the proportion equation
   70.77 : 139.61 = 139.61 : x
2. Step 2: Convert to fraction form
   70.77/139.61 = 139.61/x
3. Step 3: Cross multiply
   70.77x = 139.61 × 139.61
4. Step 4: Simplify right side
   70.77x = 19,489.69
5. Step 5: Solve for x
   x = 19,489.69/70.77
6. Step 6: Final answer
   x = 275.40