Finding the Fourth Proportional to 90.32, 135.34 and 78.69

Step by Step Solution

1. Step 1: Write the proportion equation
   90.32 : 135.34 = 78.69 : x
2. Step 2: Convert to fraction form
   90.32/135.34 = 78.69/x
3. Step 3: Cross multiply
   90.32x = 135.34 × 78.69
4. Step 4: Simplify right side
   90.32x = 10,649.90
5. Step 5: Solve for x
   x = 10,649.90/90.32
6. Step 6: Final answer
   x = 117.91