Qualification > Reference Material
Add Maths June 8, 10 2010
Ghost Of Highbury:
ohkay got it, i realized that it is on the bearing at 0600 hours, because the q was clear, screwed up while making the diagram..thanks ..
and By the way, if u zoom the angle 315 has been marked correctly, the 45 shudnt have been there :P
theharrovian:
--- Quote from: cooldude on May 30, 2010, 03:37:27 pm ---now do u mind correcting me, thanks
--- End quote ---
Your line AB is in the wrong direction - the question states "from the lifeboat", not "to the lifeboat". Otherwise your diagram is completely correct - you've just misread/misinterpreted the question and taken the lifeboat to be on a bearing of 315 from the liner.
Ghost Of Highbury:
--- Quote from: cooldude on May 30, 2010, 11:36:18 am ---see the question is basically asking what is the time taken for the boat to travel the dist AC, dist BC=54 because the speed of the liner is 36 km/h and the time it travels is 1.5 hrs thus the dist=1.5*36=54, the dist AC can be found out by the cosine rule, x=angle ABC
A^2=B^2+C^2-2ABcosx
A^2=90^2+54^2-(2*54*90*cos 135)
A=AC=133.75 km
therefore the speed of the boat = 133.75/1.5=89.2 km/h
--- End quote ---
The 315 degree bearing has been interpreted incorrectly, it shud be clockwise...bering B from A should be 315, in you case it isnt..
cooldude:
i finally understood my mistake, i took the bearing from the north direction when i was supposed to take it from the position of the liner at 600, Thanks guys ;D
jellybeans:
... D:
help please ;D
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