Finding the Fourth Proportional to 1,075.86, 1,613.61 and 426.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,075.86 : 1,613.61 = 426.42 : x
2. Step 2: Convert to fraction form
   1,075.86/1,613.61 = 426.42/x
3. Step 3: Cross multiply
   1,075.86x = 1,613.61 × 426.42
4. Step 4: Simplify right side
   1,075.86x = 688,075.58
5. Step 5: Solve for x
   x = 688,075.58/1,075.86
6. Step 6: Final answer
   x = 639.56