Finding the Fourth Proportional to 105.42, 145.34 and 91.38

Step by Step Solution

1. Step 1: Write the proportion equation
   105.42 : 145.34 = 91.38 : x
2. Step 2: Convert to fraction form
   105.42/145.34 = 91.38/x
3. Step 3: Cross multiply
   105.42x = 145.34 × 91.38
4. Step 4: Simplify right side
   105.42x = 13,281.30
5. Step 5: Solve for x
   x = 13,281.30/105.42
6. Step 6: Final answer
   x = 125.99