Finding the Fourth Proportional to 1,279.59, 1,765.81 and 720.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,279.59 : 1,765.81 = 720.05 : x
2. Step 2: Convert to fraction form
   1,279.59/1,765.81 = 720.05/x
3. Step 3: Cross multiply
   1,279.59x = 1,765.81 × 720.05
4. Step 4: Simplify right side
   1,279.59x = 1,271,474.10
5. Step 5: Solve for x
   x = 1,271,474.10/1,279.59
6. Step 6: Final answer
   x = 993.66