What is the orthocenter of a triangle with corners at #(5 ,4 )#, #(2 ,3 )#, and (3 ,8 )#?

1 Answer
Jun 26, 2018

The orthocenter of triangle is #(30/7, 29/7)#

Explanation:

Let #triangle ABC# be the triangle with corners at

#A(2,3), B(3,8) and C(5,4)#.

Let #bar(AL) ,bar(BM) and bar(CN)# be the altitudes of sides

#bar(BC) ,bar(AC) and bar(AB) # respectively.

Let #(x,y) # be the intersection of three altitudes.

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Slope of #bar(AB)=(8-3)/(3-2)#=#5=>#slope of #bar(CN)=-1/5[because#altitudes]

#and bar(CN)# passes through #C(5,4)#

So, the equn. of #bar(CN)# is :#y-4=-1/5(x-5)#

#i.e. x+5y=25... to(1)#

Slope of #bar(BC)=(8-4)/(3-5)#=#-2=>#slope of #bar(AL)=1/2[because#altitudes]

#and bar(AL)# passes through #A(2,3)#

So, the equn. of #bar(AL)# is :#y-3=1/2(x-2)#

#i.e. x-2y=-4... to(2)#

Subtracting equn.# :(1)-(2)#

#x+5y=25...to(1)#
#ul(-x+2y=4).to(2)xx(-1)#

#0+7y=29#

#=>color(red)(y=29/7#

From #(2)# we get

#x-2(29/7)=-4=>x=58/7-4=(58-28)/7#

#=>color(red)(x=30/7#

Hence , the orthocenter of triangle is #(30/7, 29/7)#