Finding the Fourth Proportional to 1,359.92, 1,876.72 and 770.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,359.92 : 1,876.72 = 770.40 : x
2. Step 2: Convert to fraction form
   1,359.92/1,876.72 = 770.40/x
3. Step 3: Cross multiply
   1,359.92x = 1,876.72 × 770.40
4. Step 4: Simplify right side
   1,359.92x = 1,445,825.09
5. Step 5: Solve for x
   x = 1,445,825.09/1,359.92
6. Step 6: Final answer
   x = 1,063.17