Finding the Fourth Proportional to 1,990.96, 2,987.34 and 821.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,990.96 : 2,987.34 = 821.82 : x
2. Step 2: Convert to fraction form
   1,990.96/2,987.34 = 821.82/x
3. Step 3: Cross multiply
   1,990.96x = 2,987.34 × 821.82
4. Step 4: Simplify right side
   1,990.96x = 2,455,055.76
5. Step 5: Solve for x
   x = 2,455,055.76/1,990.96
6. Step 6: Final answer
   x = 1,233.10