Finding the Fourth Proportional to 85,793.32, 128,690.34 and 83,719.72

Step by Step Solution

1. Step 1: Write the proportion equation
   85,793.32 : 128,690.34 = 83,719.72 : x
2. Step 2: Convert to fraction form
   85,793.32/128,690.34 = 83,719.72/x
3. Step 3: Cross multiply
   85,793.32x = 128,690.34 × 83,719.72
4. Step 4: Simplify right side
   85,793.32x = 10,773,919,231.50
5. Step 5: Solve for x
   x = 10,773,919,231.50/85,793.32
6. Step 6: Final answer
   x = 125,579.93