Finding the Fourth Proportional to 1,082.80, 1,620.56 and 900.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,082.80 : 1,620.56 = 900.55 : x
2. Step 2: Convert to fraction form
   1,082.80/1,620.56 = 900.55/x
3. Step 3: Cross multiply
   1,082.80x = 1,620.56 × 900.55
4. Step 4: Simplify right side
   1,082.80x = 1,459,390.81
5. Step 5: Solve for x
   x = 1,459,390.81/1,082.80
6. Step 6: Final answer
   x = 1,347.79