Finding the Fourth Proportional to 72.17, 99.61 and 42.68

Step by Step Solution

1. Step 1: Write the proportion equation
   72.17 : 99.61 = 42.68 : x
2. Step 2: Convert to fraction form
   72.17/99.61 = 42.68/x
3. Step 3: Cross multiply
   72.17x = 99.61 × 42.68
4. Step 4: Simplify right side
   72.17x = 4,250.91
5. Step 5: Solve for x
   x = 4,250.91/72.17
6. Step 6: Final answer
   x = 58.90