Finding the Fourth Proportional to 1,642.80, 2,267.12 and 979.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,642.80 : 2,267.12 = 979.72 : x
2. Step 2: Convert to fraction form
   1,642.80/2,267.12 = 979.72/x
3. Step 3: Cross multiply
   1,642.80x = 2,267.12 × 979.72
4. Step 4: Simplify right side
   1,642.80x = 2,221,142.81
5. Step 5: Solve for x
   x = 2,221,142.81/1,642.80
6. Step 6: Final answer
   x = 1,352.05