Finding the Fourth Proportional to 72.99, 100.85 and 58.61

Step by Step Solution

1. Step 1: Write the proportion equation
   72.99 : 100.85 = 58.61 : x
2. Step 2: Convert to fraction form
   72.99/100.85 = 58.61/x
3. Step 3: Cross multiply
   72.99x = 100.85 × 58.61
4. Step 4: Simplify right side
   72.99x = 5,910.78
5. Step 5: Solve for x
   x = 5,910.78/72.99
6. Step 6: Final answer
   x = 80.98