Finding the Fourth Proportional to 1,056.72, 1,585.12 and 765.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,056.72 : 1,585.12 = 765.12 : x
2. Step 2: Convert to fraction form
   1,056.72/1,585.12 = 765.12/x
3. Step 3: Cross multiply
   1,056.72x = 1,585.12 × 765.12
4. Step 4: Simplify right side
   1,056.72x = 1,212,807.01
5. Step 5: Solve for x
   x = 1,212,807.01/1,056.72
6. Step 6: Final answer
   x = 1,147.71