Finding the Fourth Proportional to 1,155.20, 1,731.12 and 693.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,155.20 : 1,731.12 = 693.12 : x
2. Step 2: Convert to fraction form
   1,155.20/1,731.12 = 693.12/x
3. Step 3: Cross multiply
   1,155.20x = 1,731.12 × 693.12
4. Step 4: Simplify right side
   1,155.20x = 1,199,873.89
5. Step 5: Solve for x
   x = 1,199,873.89/1,155.20
6. Step 6: Final answer
   x = 1,038.67