Finding the Fourth Proportional to 91.25, 136.22 and 78.46

Step by Step Solution

1. Step 1: Write the proportion equation
   91.25 : 136.22 = 78.46 : x
2. Step 2: Convert to fraction form
   91.25/136.22 = 78.46/x
3. Step 3: Cross multiply
   91.25x = 136.22 × 78.46
4. Step 4: Simplify right side
   91.25x = 10,687.82
5. Step 5: Solve for x
   x = 10,687.82/91.25
6. Step 6: Final answer
   x = 117.13