Finding the Fourth Proportional to 1,390.72, 1,918.92 and 893.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.72 : 1,918.92 = 893.30 : x
2. Step 2: Convert to fraction form
   1,390.72/1,918.92 = 893.30/x
3. Step 3: Cross multiply
   1,390.72x = 1,918.92 × 893.30
4. Step 4: Simplify right side
   1,390.72x = 1,714,171.24
5. Step 5: Solve for x
   x = 1,714,171.24/1,390.72
6. Step 6: Final answer
   x = 1,232.58