Finding the Fourth Proportional to 1,123.72, 1,683.72 and 891.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.72 : 1,683.72 = 891.34 : x
2. Step 2: Convert to fraction form
   1,123.72/1,683.72 = 891.34/x
3. Step 3: Cross multiply
   1,123.72x = 1,683.72 × 891.34
4. Step 4: Simplify right side
   1,123.72x = 1,500,766.98
5. Step 5: Solve for x
   x = 1,500,766.98/1,123.72
6. Step 6: Final answer
   x = 1,335.53