Finding the Fourth Proportional to 1,128.69, 1,691.67 and 992.00

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.69 : 1,691.67 = 992.00 : x
2. Step 2: Convert to fraction form
   1,128.69/1,691.67 = 992.00/x
3. Step 3: Cross multiply
   1,128.69x = 1,691.67 × 992.00
4. Step 4: Simplify right side
   1,128.69x = 1,678,141.74
5. Step 5: Solve for x
   x = 1,678,141.74/1,128.69
6. Step 6: Final answer
   x = 1,486.80