Finding the Fourth Proportional to 1,440.16, 1,987.61 and 810.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,440.16 : 1,987.61 = 810.81 : x
2. Step 2: Convert to fraction form
   1,440.16/1,987.61 = 810.81/x
3. Step 3: Cross multiply
   1,440.16x = 1,987.61 × 810.81
4. Step 4: Simplify right side
   1,440.16x = 1,611,574.57
5. Step 5: Solve for x
   x = 1,611,574.57/1,440.16
6. Step 6: Final answer
   x = 1,119.03