Finding the Fourth Proportional to 1,031.40, 1,423.98 and 716.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,031.40 : 1,423.98 = 716.57 : x
2. Step 2: Convert to fraction form
   1,031.40/1,423.98 = 716.57/x
3. Step 3: Cross multiply
   1,031.40x = 1,423.98 × 716.57
4. Step 4: Simplify right side
   1,031.40x = 1,020,376.02
5. Step 5: Solve for x
   x = 1,020,376.02/1,031.40
6. Step 6: Final answer
   x = 989.31