Finding the Fourth Proportional to 1,311.93, 1,810.59 and 979.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,311.93 : 1,810.59 = 979.78 : x
2. Step 2: Convert to fraction form
   1,311.93/1,810.59 = 979.78/x
3. Step 3: Cross multiply
   1,311.93x = 1,810.59 × 979.78
4. Step 4: Simplify right side
   1,311.93x = 1,773,973.31
5. Step 5: Solve for x
   x = 1,773,973.31/1,311.93
6. Step 6: Final answer
   x = 1,352.19