Finding the Fourth Proportional to 1,005.62, 1,386.72 and 784.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.62 : 1,386.72 = 784.20 : x
2. Step 2: Convert to fraction form
   1,005.62/1,386.72 = 784.20/x
3. Step 3: Cross multiply
   1,005.62x = 1,386.72 × 784.20
4. Step 4: Simplify right side
   1,005.62x = 1,087,465.82
5. Step 5: Solve for x
   x = 1,087,465.82/1,005.62
6. Step 6: Final answer
   x = 1,081.39