Remarks Note that the negative solution has been disregarded, because it's not physically meaningful. In checking $($step $8),$ note that the units are correct and that an approximate answer can be obtained by using the easier quantities, $500km$ and $400km.$ Doing so gives an answer of $300km,$ which is approximately the same as bur calculated answer of $270km.$

Question What is the answer if the distance traveled due east and the direct return distance are both doubled?.......

Enter a number. opriate changes in the values used in the example, or else use your knowledge of similar triangles to see quickly what the answer must be$.$