Finding the Fourth Proportional to 83.72, 124.85 and 82.91

Step by Step Solution

1. Step 1: Write the proportion equation
   83.72 : 124.85 = 82.91 : x
2. Step 2: Convert to fraction form
   83.72/124.85 = 82.91/x
3. Step 3: Cross multiply
   83.72x = 124.85 × 82.91
4. Step 4: Simplify right side
   83.72x = 10,350.27
5. Step 5: Solve for x
   x = 10,350.27/83.72
6. Step 6: Final answer
   x = 123.64