Finding the Fourth Proportional to 2,659.35, 3,987.72 and 810.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,659.35 : 3,987.72 = 810.12 : x
2. Step 2: Convert to fraction form
   2,659.35/3,987.72 = 810.12/x
3. Step 3: Cross multiply
   2,659.35x = 3,987.72 × 810.12
4. Step 4: Simplify right side
   2,659.35x = 3,230,531.73
5. Step 5: Solve for x
   x = 3,230,531.73/2,659.35
6. Step 6: Final answer
   x = 1,214.78