Finding the Fourth Proportional to 90.37, 135.42 and 78.22

Step by Step Solution

1. Step 1: Write the proportion equation
   90.37 : 135.42 = 78.22 : x
2. Step 2: Convert to fraction form
   90.37/135.42 = 78.22/x
3. Step 3: Cross multiply
   90.37x = 135.42 × 78.22
4. Step 4: Simplify right side
   90.37x = 10,592.55
5. Step 5: Solve for x
   x = 10,592.55/90.37
6. Step 6: Final answer
   x = 117.21