Parvesh travels 15m toward north, turns right and travels 20m. Then turns
left and travels 5m. How far is he from the starting point and in which
direction?
Answers
Given :- Parvesh travels 15m toward north, turns right and travels 20m. Then turns left and travels 5m.
To Find :- How far is he from the starting point and in which direction ?
Solution :-
from image let Pravesh travel from point A and walks towards north and after 15 m stops at point B .
So,
→ AB = 15 m
now, from point B he turns right and walks another 20 m and stops at point C .
So,
→ BC = 20 m .
now, from point B he turns left and walks another 5 m and stops at point D .
So,
→ CD = 5 m .
Now, we have,
→ A = Starting point .
→ D = End point .
Let us assume that, BE = x m .
In ∆ABE and ∆DCE we have,
→ ∠ABE = ∠DCE { Each 90° }
→ ∠BEA = CED { Vertically opposite angles }
So,
→ ∆ABE ~ ∆DCE { By AA similarity. }
then,
→ AB/DC = BE/CE { When two ∆'s are similar their corresponding sides are in same ratio . }
→ 15/5 = x/(20 - x)
→ 3(20 - x) = x
→ 60 - 3x = x
→ 60 = x + 3x
→ 4x = 60
→ x = 15 m
therefore,
→ BE = 15 m
→ CE = BC - BE = 20 - 15 = 5 m .
now, in right angled ∆ABC right angle at E we have,
→ AE = √(AB² + BE²) { By pythagoras theorem }
→ AE = √(15² + 15²)
→ AE = √(225 + 225)
→ AE = √(2 × 225)
→ AE = 15√2 m
similarly, in right angled ∆DCE right angle at E we have,
→ DE = √(DC² + CE²) { By pythagoras theorem }
→ DE = √(5² + 5²)
→ DE = √(25 + 25)
→ DE = √(2 × 25)
→ DE = 5√2 m
hence,
→ AD = AE + DE = AE + ED = 15√2 + 5√2 = 20√2 m (Ans.)
also,
→ Direction of point D from point A = North - East (Ans.)
∴ Parvesh is 20√2 m away from the starting point and in North - East direction .
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