Finding the Fourth Proportional to 89.56, 134.04 and 78.72

Step by Step Solution

1. Step 1: Write the proportion equation
   89.56 : 134.04 = 78.72 : x
2. Step 2: Convert to fraction form
   89.56/134.04 = 78.72/x
3. Step 3: Cross multiply
   89.56x = 134.04 × 78.72
4. Step 4: Simplify right side
   89.56x = 10,551.63
5. Step 5: Solve for x
   x = 10,551.63/89.56
6. Step 6: Final answer
   x = 117.82