Finding the Fourth Proportional to 1,991.46, 2,986.72 and 820.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,991.46 : 2,986.72 = 820.30 : x
2. Step 2: Convert to fraction form
   1,991.46/2,986.72 = 820.30/x
3. Step 3: Cross multiply
   1,991.46x = 2,986.72 × 820.30
4. Step 4: Simplify right side
   1,991.46x = 2,450,015.51
5. Step 5: Solve for x
   x = 2,450,015.51/1,991.46
6. Step 6: Final answer
   x = 1,230.26