Finding the Fourth Proportional to 1,436.58, 2,155.28 and 821.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,436.58 : 2,155.28 = 821.39 : x
2. Step 2: Convert to fraction form
   1,436.58/2,155.28 = 821.39/x
3. Step 3: Cross multiply
   1,436.58x = 2,155.28 × 821.39
4. Step 4: Simplify right side
   1,436.58x = 1,770,310.56
5. Step 5: Solve for x
   x = 1,770,310.56/1,436.58
6. Step 6: Final answer
   x = 1,232.31