Finding the Fourth Proportional to 1,081.72, 1,491.30 and 787

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.72 : 1,491.30 = 787 : x
2. Step 2: Convert to fraction form
   1,081.72/1,491.30 = 787/x
3. Step 3: Cross multiply
   1,081.72x = 1,491.30 × 787
4. Step 4: Simplify right side
   1,081.72x = 1,173,653.10
5. Step 5: Solve for x
   x = 1,173,653.10/1,081.72
6. Step 6: Final answer
   x = 1,084.99