Finding the Fourth Proportional to 105.42, 145.79 and 100.59

Step by Step Solution

1. Step 1: Write the proportion equation
   105.42 : 145.79 = 100.59 : x
2. Step 2: Convert to fraction form
   105.42/145.79 = 100.59/x
3. Step 3: Cross multiply
   105.42x = 145.79 × 100.59
4. Step 4: Simplify right side
   105.42x = 14,664.34
5. Step 5: Solve for x
   x = 14,664.34/105.42
6. Step 6: Final answer
   x = 139.10