Finding the Fourth Proportional to 1,108.64, 1,529.60 and 715.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,108.64 : 1,529.60 = 715.89 : x
2. Step 2: Convert to fraction form
   1,108.64/1,529.60 = 715.89/x
3. Step 3: Cross multiply
   1,108.64x = 1,529.60 × 715.89
4. Step 4: Simplify right side
   1,108.64x = 1,095,021.76
5. Step 5: Solve for x
   x = 1,095,021.76/1,108.64
6. Step 6: Final answer
   x = 987.72