Finding the Fourth Proportional to 105.42, 145.50 and 72.69

Step by Step Solution

1. Step 1: Write the proportion equation
   105.42 : 145.50 = 72.69 : x
2. Step 2: Convert to fraction form
   105.42/145.50 = 72.69/x
3. Step 3: Cross multiply
   105.42x = 145.50 × 72.69
4. Step 4: Simplify right side
   105.42x = 10,576.40
5. Step 5: Solve for x
   x = 10,576.40/105.42
6. Step 6: Final answer
   x = 100.33