Finding the Fourth Proportional to 100.86, 139.18 and 59.42

Step by Step Solution

1. Step 1: Write the proportion equation
   100.86 : 139.18 = 59.42 : x
2. Step 2: Convert to fraction form
   100.86/139.18 = 59.42/x
3. Step 3: Cross multiply
   100.86x = 139.18 × 59.42
4. Step 4: Simplify right side
   100.86x = 8,269.73
5. Step 5: Solve for x
   x = 8,269.73/100.86
6. Step 6: Final answer
   x = 81.99