Finding the Fourth Proportional to 100.84, 151.32 and 91.78

Step by Step Solution

1. Step 1: Write the proportion equation
   100.84 : 151.32 = 91.78 : x
2. Step 2: Convert to fraction form
   100.84/151.32 = 91.78/x
3. Step 3: Cross multiply
   100.84x = 151.32 × 91.78
4. Step 4: Simplify right side
   100.84x = 13,888.15
5. Step 5: Solve for x
   x = 13,888.15/100.84
6. Step 6: Final answer
   x = 137.72