Finding the Fourth Proportional to 100.99, 151.32 and 80.69

Step by Step Solution

1. Step 1: Write the proportion equation
   100.99 : 151.32 = 80.69 : x
2. Step 2: Convert to fraction form
   100.99/151.32 = 80.69/x
3. Step 3: Cross multiply
   100.99x = 151.32 × 80.69
4. Step 4: Simplify right side
   100.99x = 12,210.01
5. Step 5: Solve for x
   x = 12,210.01/100.99
6. Step 6: Final answer
   x = 120.91