Finding the Fourth Proportional to 82.13, 123.72 and 81.73

Step by Step Solution

1. Step 1: Write the proportion equation
   82.13 : 123.72 = 81.73 : x
2. Step 2: Convert to fraction form
   82.13/123.72 = 81.73/x
3. Step 3: Cross multiply
   82.13x = 123.72 × 81.73
4. Step 4: Simplify right side
   82.13x = 10,111.64
5. Step 5: Solve for x
   x = 10,111.64/82.13
6. Step 6: Final answer
   x = 123.12