Finding the Fourth Proportional to 2,021.31, 2,788.72 and 1,224.88

Step by Step Solution

1. Step 1: Write the proportion equation
   2,021.31 : 2,788.72 = 1,224.88 : x
2. Step 2: Convert to fraction form
   2,021.31/2,788.72 = 1,224.88/x
3. Step 3: Cross multiply
   2,021.31x = 2,788.72 × 1,224.88
4. Step 4: Simplify right side
   2,021.31x = 3,415,837.32
5. Step 5: Solve for x
   x = 3,415,837.32/2,021.31
6. Step 6: Final answer
   x = 1,689.91