Finding the Fourth Proportional to 1,075.80, 1,613.72 and 861.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,075.80 : 1,613.72 = 861.96 : x
2. Step 2: Convert to fraction form
   1,075.80/1,613.72 = 861.96/x
3. Step 3: Cross multiply
   1,075.80x = 1,613.72 × 861.96
4. Step 4: Simplify right side
   1,075.80x = 1,390,962.09
5. Step 5: Solve for x
   x = 1,390,962.09/1,075.80
6. Step 6: Final answer
   x = 1,292.96