Finding the Fourth Proportional to 86,909.68, 130,456.64 and 76,978.88

Step by Step Solution

1. Step 1: Write the proportion equation
   86,909.68 : 130,456.64 = 76,978.88 : x
2. Step 2: Convert to fraction form
   86,909.68/130,456.64 = 76,978.88/x
3. Step 3: Cross multiply
   86,909.68x = 130,456.64 × 76,978.88
4. Step 4: Simplify right side
   86,909.68x = 10,042,406,035.76
5. Step 5: Solve for x
   x = 10,042,406,035.76/86,909.68
6. Step 6: Final answer
   x = 115,549.91