Finding the Fourth Proportional to 1,451.60, 2,002.72 and 861.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,451.60 : 2,002.72 = 861.80 : x
2. Step 2: Convert to fraction form
   1,451.60/2,002.72 = 861.80/x
3. Step 3: Cross multiply
   1,451.60x = 2,002.72 × 861.80
4. Step 4: Simplify right side
   1,451.60x = 1,725,944.10
5. Step 5: Solve for x
   x = 1,725,944.10/1,451.60
6. Step 6: Final answer
   x = 1,188.99