Finding the Fourth Proportional to 1,479.35, 2,216.72 and 861.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,479.35 : 2,216.72 = 861.53 : x
2. Step 2: Convert to fraction form
   1,479.35/2,216.72 = 861.53/x
3. Step 3: Cross multiply
   1,479.35x = 2,216.72 × 861.53
4. Step 4: Simplify right side
   1,479.35x = 1,909,755.39
5. Step 5: Solve for x
   x = 1,909,755.39/1,479.35
6. Step 6: Final answer
   x = 1,290.95