Finding the Fourth Proportional to 1,002.88, 1,507.68 and 821.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,002.88 : 1,507.68 = 821.62 : x
2. Step 2: Convert to fraction form
   1,002.88/1,507.68 = 821.62/x
3. Step 3: Cross multiply
   1,002.88x = 1,507.68 × 821.62
4. Step 4: Simplify right side
   1,002.88x = 1,238,740.04
5. Step 5: Solve for x
   x = 1,238,740.04/1,002.88
6. Step 6: Final answer
   x = 1,235.18