Finding the Fourth Proportional to 105.72, 145.76 and 74.58

Step by Step Solution

1. Step 1: Write the proportion equation
   105.72 : 145.76 = 74.58 : x
2. Step 2: Convert to fraction form
   105.72/145.76 = 74.58/x
3. Step 3: Cross multiply
   105.72x = 145.76 × 74.58
4. Step 4: Simplify right side
   105.72x = 10,870.41
5. Step 5: Solve for x
   x = 10,870.41/105.72
6. Step 6: Final answer
   x = 102.82