Finding the Fourth Proportional to 1,081.20, 1,490.50 and 770.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.20 : 1,490.50 = 770.16 : x
2. Step 2: Convert to fraction form
   1,081.20/1,490.50 = 770.16/x
3. Step 3: Cross multiply
   1,081.20x = 1,490.50 × 770.16
4. Step 4: Simplify right side
   1,081.20x = 1,147,914.52
5. Step 5: Solve for x
   x = 1,147,914.52/1,081.20
6. Step 6: Final answer
   x = 1,061.71