Finding the Third Proportional to 31.13 and 42.80

Step by Step Solution

1. Step 1: Write the proportion equation
   31.13 : 42.80 = 42.80 : x
2. Step 2: Convert to fraction form
   31.13/42.80 = 42.80/x
3. Step 3: Cross multiply
   31.13x = 42.80 × 42.80
4. Step 4: Simplify right side
   31.13x = 1,831.57
5. Step 5: Solve for x
   x = 1,831.57/31.13
6. Step 6: Final answer
   x = 58.85