Finding the Fourth Proportional to 2,142.80, 3,214.61 and 988.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,142.80 : 3,214.61 = 988.55 : x
2. Step 2: Convert to fraction form
   2,142.80/3,214.61 = 988.55/x
3. Step 3: Cross multiply
   2,142.80x = 3,214.61 × 988.55
4. Step 4: Simplify right side
   2,142.80x = 3,177,802.72
5. Step 5: Solve for x
   x = 3,177,802.72/2,142.80
6. Step 6: Final answer
   x = 1,483.01