Finding the Fourth Proportional to 1,390.79, 1,918.71 and 893.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.79 : 1,918.71 = 893.72 : x
2. Step 2: Convert to fraction form
   1,390.79/1,918.71 = 893.72/x
3. Step 3: Cross multiply
   1,390.79x = 1,918.71 × 893.72
4. Step 4: Simplify right side
   1,390.79x = 1,714,779.91
5. Step 5: Solve for x
   x = 1,714,779.91/1,390.79
6. Step 6: Final answer
   x = 1,232.96