Finding the Fourth Proportional to 2,001.78, 2,763.18 and 1,215.81

Step by Step Solution

1. Step 1: Write the proportion equation
   2,001.78 : 2,763.18 = 1,215.81 : x
2. Step 2: Convert to fraction form
   2,001.78/2,763.18 = 1,215.81/x
3. Step 3: Cross multiply
   2,001.78x = 2,763.18 × 1,215.81
4. Step 4: Simplify right side
   2,001.78x = 3,359,501.88
5. Step 5: Solve for x
   x = 3,359,501.88/2,001.78
6. Step 6: Final answer
   x = 1,678.26