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Sam goes $\sqrt{12.5}$ km towards west from a certain point. Then after turning to his right he again goes same distance. In the end he goes 25 km towards south-east. How far is he from the starting point.

Isn't he at the origin point (i.e. from where he started) or am I mistaken?

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    @AndréNicolas I guess you maybe right, the answer of$20$km would be correct, if he travelled$5$km SE instead of 25 km SE. The question seems to be incorrect.2012-07-01

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The way the question is currently stated, Sam winds up 20km from the starting point.

Call the starting point $A$.

Sam goes $\sqrt{12.5}$km west and gets to a point we'll call $B$.

Sam goes $\sqrt{12.5}$km north and gets to a point we'll call $C$.

Now $ABC$ is an isosceles right triangle with right angle at $B$ (we are ignoring curvature of the Earth here, and treating it as a plane. If Sam started $\sqrt{12.5}$km south of the North Pole, all bets are off). By Pythagoras, $A$ is 5km southeast of $C$. So if Sam now goes 25km to the southeast, he goes 20km past $A$, winding up 20km from the starting point.

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    Looks that way to me.2012-07-02
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Correct. He traverses the edges of a 45-45-90 triangle. Your answer is right.

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    The answer was mistakenly provided as 20 km(s) for the above question. Guess it was incorrect.2012-07-01