Finding the Fourth Proportional to 1,931.72, 2,665.04 and 1,428.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,931.72 : 2,665.04 = 1,428.78 : x
2. Step 2: Convert to fraction form
   1,931.72/2,665.04 = 1,428.78/x
3. Step 3: Cross multiply
   1,931.72x = 2,665.04 × 1,428.78
4. Step 4: Simplify right side
   1,931.72x = 3,807,746.10
5. Step 5: Solve for x
   x = 3,807,746.10/1,931.72
6. Step 6: Final answer
   x = 1,971.17