Finding the Fourth Proportional to 28,140.38, 42,211.98 and 8,419.10

Step by Step Solution

1. Step 1: Write the proportion equation
   28,140.38 : 42,211.98 = 8,419.10 : x
2. Step 2: Convert to fraction form
   28,140.38/42,211.98 = 8,419.10/x
3. Step 3: Cross multiply
   28,140.38x = 42,211.98 × 8,419.10
4. Step 4: Simplify right side
   28,140.38x = 355,386,880.82
5. Step 5: Solve for x
   x = 355,386,880.82/28,140.38
6. Step 6: Final answer
   x = 12,629.07