Finding the Third Proportional to 31.17 and 72.80

Step by Step Solution

1. Step 1: Write the proportion equation
   31.17 : 72.80 = 72.80 : x
2. Step 2: Convert to fraction form
   31.17/72.80 = 72.80/x
3. Step 3: Cross multiply
   31.17x = 72.80 × 72.80
4. Step 4: Simplify right side
   31.17x = 5,299.39
5. Step 5: Solve for x
   x = 5,299.39/31.17
6. Step 6: Final answer
   x = 170.01