Finding the Fourth Proportional to 2,381.40, 3,570.89 and 821.34

Step by Step Solution

1. Step 1: Write the proportion equation
   2,381.40 : 3,570.89 = 821.34 : x
2. Step 2: Convert to fraction form
   2,381.40/3,570.89 = 821.34/x
3. Step 3: Cross multiply
   2,381.40x = 3,570.89 × 821.34
4. Step 4: Simplify right side
   2,381.40x = 2,932,910.69
5. Step 5: Solve for x
   x = 2,932,910.69/2,381.40
6. Step 6: Final answer
   x = 1,231.59