Finding the Fourth Proportional to 100.42, 138.53 and 67.61

Step by Step Solution

1. Step 1: Write the proportion equation
   100.42 : 138.53 = 67.61 : x
2. Step 2: Convert to fraction form
   100.42/138.53 = 67.61/x
3. Step 3: Cross multiply
   100.42x = 138.53 × 67.61
4. Step 4: Simplify right side
   100.42x = 9,366.61
5. Step 5: Solve for x
   x = 9,366.61/100.42
6. Step 6: Final answer
   x = 93.28