Finding the Fourth Proportional to 1,439.96, 1,987.12 and 810.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.96 : 1,987.12 = 810.50 : x
2. Step 2: Convert to fraction form
   1,439.96/1,987.12 = 810.50/x
3. Step 3: Cross multiply
   1,439.96x = 1,987.12 × 810.50
4. Step 4: Simplify right side
   1,439.96x = 1,610,560.76
5. Step 5: Solve for x
   x = 1,610,560.76/1,439.96
6. Step 6: Final answer
   x = 1,118.48