Finding the Fourth Proportional to 91.78, 137.59 and 61.33

Step by Step Solution

1. Step 1: Write the proportion equation
   91.78 : 137.59 = 61.33 : x
2. Step 2: Convert to fraction form
   91.78/137.59 = 61.33/x
3. Step 3: Cross multiply
   91.78x = 137.59 × 61.33
4. Step 4: Simplify right side
   91.78x = 8,438.39
5. Step 5: Solve for x
   x = 8,438.39/91.78
6. Step 6: Final answer
   x = 91.94