Finding the Fourth Proportional to 78,071.92, 117,036.12 and 28,139.80

Step by Step Solution

1. Step 1: Write the proportion equation
   78,071.92 : 117,036.12 = 28,139.80 : x
2. Step 2: Convert to fraction form
   78,071.92/117,036.12 = 28,139.80/x
3. Step 3: Cross multiply
   78,071.92x = 117,036.12 × 28,139.80
4. Step 4: Simplify right side
   78,071.92x = 3,293,373,009.58
5. Step 5: Solve for x
   x = 3,293,373,009.58/78,071.92
6. Step 6: Final answer
   x = 42,183.84