Finding the Third Proportional to 31.78 and 72.28

Step by Step Solution

1. Step 1: Write the proportion equation
   31.78 : 72.28 = 72.28 : x
2. Step 2: Convert to fraction form
   31.78/72.28 = 72.28/x
3. Step 3: Cross multiply
   31.78x = 72.28 × 72.28
4. Step 4: Simplify right side
   31.78x = 5,224.58
5. Step 5: Solve for x
   x = 5,224.58/31.78
6. Step 6: Final answer
   x = 164.39