Finding the Fourth Proportional to 1,215.69, 1,678.15 and 822.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.69 : 1,678.15 = 822.94 : x
2. Step 2: Convert to fraction form
   1,215.69/1,678.15 = 822.94/x
3. Step 3: Cross multiply
   1,215.69x = 1,678.15 × 822.94
4. Step 4: Simplify right side
   1,215.69x = 1,381,016.76
5. Step 5: Solve for x
   x = 1,381,016.76/1,215.69
6. Step 6: Final answer
   x = 1,135.99