Finding the Fourth Proportional to 1,399.72, 1,931.40 and 902.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.72 : 1,931.40 = 902.38 : x
2. Step 2: Convert to fraction form
   1,399.72/1,931.40 = 902.38/x
3. Step 3: Cross multiply
   1,399.72x = 1,931.40 × 902.38
4. Step 4: Simplify right side
   1,399.72x = 1,742,856.73
5. Step 5: Solve for x
   x = 1,742,856.73/1,399.72
6. Step 6: Final answer
   x = 1,245.15