Finding the Fourth Proportional to 28,429.25, 42,645.69 and 8,721.54

Step by Step Solution

1. Step 1: Write the proportion equation
   28,429.25 : 42,645.69 = 8,721.54 : x
2. Step 2: Convert to fraction form
   28,429.25/42,645.69 = 8,721.54/x
3. Step 3: Cross multiply
   28,429.25x = 42,645.69 × 8,721.54
4. Step 4: Simplify right side
   28,429.25x = 371,936,091.16
5. Step 5: Solve for x
   x = 371,936,091.16/28,429.25
6. Step 6: Final answer
   x = 13,082.87