Finding the Fourth Proportional to 1,056.69, 1,580.38 and 959.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,056.69 : 1,580.38 = 959.81 : x
2. Step 2: Convert to fraction form
   1,056.69/1,580.38 = 959.81/x
3. Step 3: Cross multiply
   1,056.69x = 1,580.38 × 959.81
4. Step 4: Simplify right side
   1,056.69x = 1,516,854.23
5. Step 5: Solve for x
   x = 1,516,854.23/1,056.69
6. Step 6: Final answer
   x = 1,435.48