Finding the Fourth Proportional to 89.59, 134.23 and 78.70

Step by Step Solution

1. Step 1: Write the proportion equation
   89.59 : 134.23 = 78.70 : x
2. Step 2: Convert to fraction form
   89.59/134.23 = 78.70/x
3. Step 3: Cross multiply
   89.59x = 134.23 × 78.70
4. Step 4: Simplify right side
   89.59x = 10,563.90
5. Step 5: Solve for x
   x = 10,563.90/89.59
6. Step 6: Final answer
   x = 117.91