Finding the Fourth Proportional to 88.47, 131.99 and 78.72

Step by Step Solution

1. Step 1: Write the proportion equation
   88.47 : 131.99 = 78.72 : x
2. Step 2: Convert to fraction form
   88.47/131.99 = 78.72/x
3. Step 3: Cross multiply
   88.47x = 131.99 × 78.72
4. Step 4: Simplify right side
   88.47x = 10,390.15
5. Step 5: Solve for x
   x = 10,390.15/88.47
6. Step 6: Final answer
   x = 117.45