Finding the Fourth Proportional to 1,007.69, 1,390.64 and 588.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.69 : 1,390.64 = 588.06 : x
2. Step 2: Convert to fraction form
   1,007.69/1,390.64 = 588.06/x
3. Step 3: Cross multiply
   1,007.69x = 1,390.64 × 588.06
4. Step 4: Simplify right side
   1,007.69x = 817,776.82
5. Step 5: Solve for x
   x = 817,776.82/1,007.69
6. Step 6: Final answer
   x = 811.54