Finding the Fourth Proportional to 100.68, 150.69 and 91.21

Step by Step Solution

1. Step 1: Write the proportion equation
   100.68 : 150.69 = 91.21 : x
2. Step 2: Convert to fraction form
   100.68/150.69 = 91.21/x
3. Step 3: Cross multiply
   100.68x = 150.69 × 91.21
4. Step 4: Simplify right side
   100.68x = 13,744.43
5. Step 5: Solve for x
   x = 13,744.43/100.68
6. Step 6: Final answer
   x = 136.52