Finding the Fourth Proportional to 1,438.72, 1,985.42 and 817.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,438.72 : 1,985.42 = 817.72 : x
2. Step 2: Convert to fraction form
   1,438.72/1,985.42 = 817.72/x
3. Step 3: Cross multiply
   1,438.72x = 1,985.42 × 817.72
4. Step 4: Simplify right side
   1,438.72x = 1,623,503.63
5. Step 5: Solve for x
   x = 1,623,503.63/1,438.72
6. Step 6: Final answer
   x = 1,128.44