Finding the Fourth Proportional to 100.72, 151.32 and 86.32

Step by Step Solution

1. Step 1: Write the proportion equation
   100.72 : 151.32 = 86.32 : x
2. Step 2: Convert to fraction form
   100.72/151.32 = 86.32/x
3. Step 3: Cross multiply
   100.72x = 151.32 × 86.32
4. Step 4: Simplify right side
   100.72x = 13,061.94
5. Step 5: Solve for x
   x = 13,061.94/100.72
6. Step 6: Final answer
   x = 129.69