Finding the Fourth Proportional to 1,279.89, 1,766.42 and 720.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,279.89 : 1,766.42 = 720.47 : x
2. Step 2: Convert to fraction form
   1,279.89/1,766.42 = 720.47/x
3. Step 3: Cross multiply
   1,279.89x = 1,766.42 × 720.47
4. Step 4: Simplify right side
   1,279.89x = 1,272,649.51
5. Step 5: Solve for x
   x = 1,272,649.51/1,279.89
6. Step 6: Final answer
   x = 994.34