Finding the Fourth Proportional to 2,820.89, 4,231.79 and 971.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,820.89 : 4,231.79 = 971.55 : x
2. Step 2: Convert to fraction form
   2,820.89/4,231.79 = 971.55/x
3. Step 3: Cross multiply
   2,820.89x = 4,231.79 × 971.55
4. Step 4: Simplify right side
   2,820.89x = 4,111,390.72
5. Step 5: Solve for x
   x = 4,111,390.72/2,820.89
6. Step 6: Final answer
   x = 1,457.48