Finding the Fourth Proportional to 1,187.20, 1,636.80 and 1,150.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,187.20 : 1,636.80 = 1,150.72 : x
2. Step 2: Convert to fraction form
   1,187.20/1,636.80 = 1,150.72/x
3. Step 3: Cross multiply
   1,187.20x = 1,636.80 × 1,150.72
4. Step 4: Simplify right side
   1,187.20x = 1,883,498.50
5. Step 5: Solve for x
   x = 1,883,498.50/1,187.20
6. Step 6: Final answer
   x = 1,586.50