Finding the Fourth Proportional to 2,012.39, 2,778.20 and 1,215.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,012.39 : 2,778.20 = 1,215.86 : x
2. Step 2: Convert to fraction form
   2,012.39/2,778.20 = 1,215.86/x
3. Step 3: Cross multiply
   2,012.39x = 2,778.20 × 1,215.86
4. Step 4: Simplify right side
   2,012.39x = 3,377,902.47
5. Step 5: Solve for x
   x = 3,377,902.47/2,012.39
6. Step 6: Final answer
   x = 1,678.55