Finding the Fourth Proportional to 105.57, 145.58 and 68.72

Step by Step Solution

1. Step 1: Write the proportion equation
   105.57 : 145.58 = 68.72 : x
2. Step 2: Convert to fraction form
   105.57/145.58 = 68.72/x
3. Step 3: Cross multiply
   105.57x = 145.58 × 68.72
4. Step 4: Simplify right side
   105.57x = 10,003.19
5. Step 5: Solve for x
   x = 10,003.19/105.57
6. Step 6: Final answer
   x = 94.75