Finding the Fourth Proportional to 3,421.12, 5,130.72 and 1,081.30

Step by Step Solution

1. Step 1: Write the proportion equation
   3,421.12 : 5,130.72 = 1,081.30 : x
2. Step 2: Convert to fraction form
   3,421.12/5,130.72 = 1,081.30/x
3. Step 3: Cross multiply
   3,421.12x = 5,130.72 × 1,081.30
4. Step 4: Simplify right side
   3,421.12x = 5,547,847.54
5. Step 5: Solve for x
   x = 5,547,847.54/3,421.12
6. Step 6: Final answer
   x = 1,621.65