Finding the Third Proportional to 31.13 and 64.78

Step by Step Solution

1. Step 1: Write the proportion equation
   31.13 : 64.78 = 64.78 : x
2. Step 2: Convert to fraction form
   31.13/64.78 = 64.78/x
3. Step 3: Cross multiply
   31.13x = 64.78 × 64.78
4. Step 4: Simplify right side
   31.13x = 4,196.61
5. Step 5: Solve for x
   x = 4,196.61/31.13
6. Step 6: Final answer
   x = 134.83