Finding the Fourth Proportional to 128,078.56, 176,742.72 and 71,488.64

Step by Step Solution

1. Step 1: Write the proportion equation
   128,078.56 : 176,742.72 = 71,488.64 : x
2. Step 2: Convert to fraction form
   128,078.56/176,742.72 = 71,488.64/x
3. Step 3: Cross multiply
   128,078.56x = 176,742.72 × 71,488.64
4. Step 4: Simplify right side
   128,078.56x = 12,635,096,682.70
5. Step 5: Solve for x
   x = 12,635,096,682.70/128,078.56
6. Step 6: Final answer
   x = 98,651.15