Finding the Fourth Proportional to 83.38, 124.72 and 81.17

Step by Step Solution

1. Step 1: Write the proportion equation
   83.38 : 124.72 = 81.17 : x
2. Step 2: Convert to fraction form
   83.38/124.72 = 81.17/x
3. Step 3: Cross multiply
   83.38x = 124.72 × 81.17
4. Step 4: Simplify right side
   83.38x = 10,123.32
5. Step 5: Solve for x
   x = 10,123.32/83.38
6. Step 6: Final answer
   x = 121.41