Finding the Fourth Proportional to 1,123.98, 1,686.20 and 343.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.98 : 1,686.20 = 343.96 : x
2. Step 2: Convert to fraction form
   1,123.98/1,686.20 = 343.96/x
3. Step 3: Cross multiply
   1,123.98x = 1,686.20 × 343.96
4. Step 4: Simplify right side
   1,123.98x = 579,985.35
5. Step 5: Solve for x
   x = 579,985.35/1,123.98
6. Step 6: Final answer
   x = 516.01