Finding the Fourth Proportional to 1,279.59, 1,765.77 and 720.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,279.59 : 1,765.77 = 720.15 : x
2. Step 2: Convert to fraction form
   1,279.59/1,765.77 = 720.15/x
3. Step 3: Cross multiply
   1,279.59x = 1,765.77 × 720.15
4. Step 4: Simplify right side
   1,279.59x = 1,271,619.27
5. Step 5: Solve for x
   x = 1,271,619.27/1,279.59
6. Step 6: Final answer
   x = 993.77