Finding the Fourth Proportional to 80,395, 120,664.78 and 42,987.05

Step by Step Solution

1. Step 1: Write the proportion equation
   80,395 : 120,664.78 = 42,987.05 : x
2. Step 2: Convert to fraction form
   80,395/120,664.78 = 42,987.05/x
3. Step 3: Cross multiply
   80,395x = 120,664.78 × 42,987.05
4. Step 4: Simplify right side
   80,395x = 5,187,022,716.16
5. Step 5: Solve for x
   x = 5,187,022,716.16/80,395
6. Step 6: Final answer
   x = 64,519.22