Finding the Fourth Proportional to 86,456.80, 128,775.96 and 82,412

Step by Step Solution

1. Step 1: Write the proportion equation
   86,456.80 : 128,775.96 = 82,412 : x
2. Step 2: Convert to fraction form
   86,456.80/128,775.96 = 82,412/x
3. Step 3: Cross multiply
   86,456.80x = 128,775.96 × 82,412
4. Step 4: Simplify right side
   86,456.80x = 10,612,684,415.52
5. Step 5: Solve for x
   x = 10,612,684,415.52/86,456.80
6. Step 6: Final answer
   x = 122,751.30