Finding the Fourth Proportional to 106.40, 159.72 and 100.72

Step by Step Solution

1. Step 1: Write the proportion equation
   106.40 : 159.72 = 100.72 : x
2. Step 2: Convert to fraction form
   106.40/159.72 = 100.72/x
3. Step 3: Cross multiply
   106.40x = 159.72 × 100.72
4. Step 4: Simplify right side
   106.40x = 16,087.00
5. Step 5: Solve for x
   x = 16,087.00/106.40
6. Step 6: Final answer
   x = 151.19