Finding the Fourth Proportional to 109.56, 164.16 and 78.96

Step by Step Solution

1. Step 1: Write the proportion equation
   109.56 : 164.16 = 78.96 : x
2. Step 2: Convert to fraction form
   109.56/164.16 = 78.96/x
3. Step 3: Cross multiply
   109.56x = 164.16 × 78.96
4. Step 4: Simplify right side
   109.56x = 12,962.07
5. Step 5: Solve for x
   x = 12,962.07/109.56
6. Step 6: Final answer
   x = 118.31