Finding the Fourth Proportional to 2,859.77, 4,286.72 and 1,215.47

Step by Step Solution

1. Step 1: Write the proportion equation
   2,859.77 : 4,286.72 = 1,215.47 : x
2. Step 2: Convert to fraction form
   2,859.77/4,286.72 = 1,215.47/x
3. Step 3: Cross multiply
   2,859.77x = 4,286.72 × 1,215.47
4. Step 4: Simplify right side
   2,859.77x = 5,210,393.31
5. Step 5: Solve for x
   x = 5,210,393.31/2,859.77
6. Step 6: Final answer
   x = 1,821.96