Finding the Fourth Proportional to 100.29, 138.45 and 72.69

Step by Step Solution

1. Step 1: Write the proportion equation
   100.29 : 138.45 = 72.69 : x
2. Step 2: Convert to fraction form
   100.29/138.45 = 72.69/x
3. Step 3: Cross multiply
   100.29x = 138.45 × 72.69
4. Step 4: Simplify right side
   100.29x = 10,063.93
5. Step 5: Solve for x
   x = 10,063.93/100.29
6. Step 6: Final answer
   x = 100.35