Finding the Fourth Proportional to 82.15, 123.15 and 43.61

Step by Step Solution

1. Step 1: Write the proportion equation
   82.15 : 123.15 = 43.61 : x
2. Step 2: Convert to fraction form
   82.15/123.15 = 43.61/x
3. Step 3: Cross multiply
   82.15x = 123.15 × 43.61
4. Step 4: Simplify right side
   82.15x = 5,370.57
5. Step 5: Solve for x
   x = 5,370.57/82.15
6. Step 6: Final answer
   x = 65.38