Finding the Fourth Proportional to 1,242.69, 1,714.86 and 718.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,242.69 : 1,714.86 = 718.71 : x
2. Step 2: Convert to fraction form
   1,242.69/1,714.86 = 718.71/x
3. Step 3: Cross multiply
   1,242.69x = 1,714.86 × 718.71
4. Step 4: Simplify right side
   1,242.69x = 1,232,487.03
5. Step 5: Solve for x
   x = 1,232,487.03/1,242.69
6. Step 6: Final answer
   x = 991.79