Finding the Fourth Proportional to 1,123.78, 1,684.30 and 992.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.78 : 1,684.30 = 992.56 : x
2. Step 2: Convert to fraction form
   1,123.78/1,684.30 = 992.56/x
3. Step 3: Cross multiply
   1,123.78x = 1,684.30 × 992.56
4. Step 4: Simplify right side
   1,123.78x = 1,671,768.81
5. Step 5: Solve for x
   x = 1,671,768.81/1,123.78
6. Step 6: Final answer
   x = 1,487.63