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Find the coordinates of the orthocenter of the triangle whose vertices are A(3, 1), B(0, 4) and C(-3, 1).​

User Lomelisan
by
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1 Answer

20 votes
20 votes
The point of intersection of two perpendicular drawn from any two vertices of the triangle is known as orthocenter.
Let us consider the perpendicular drawn from A is AD and perpendicular drawn from the vertex B is BE.
Slope of AC = [(y2 - y1)/(x2 - x1)]
A (3, 1) and C (-3, 1)
here x1 = 3, x2 = -3, y1 = 1 and y2 = 1
= (1 - 1) / (-3 - 3)
= 0 / (-6)
= 0
Slope of the altitude BE = -1/ slope of AC
= -1/0
Equation of the altitude BE :
(y - y1) = m (x -x1)
Here B (0, 4) and m = -1/0
(y - 4) = -1/0 (x - 0)
10 (y - 4) = -1(x)
x + 10y - 40 = 0 --------(1)
Slope of BC = (y2 - y1)(x2 - x1)]
B (0, 4) and C (-3, 1)
Here x1 = 0, x2 = -3, y1 = 4 and y2 = 1.
= (1 - 4) / (-3 - 0)
= (-3)/(-3)
= 1
Slope of the altitude AD = -1/ slope of AC
= -1/1
= -1
Equation of the altitude AD :
(y - y1) = m (x - x1)
Here A(3, 1) m = -1
(y - 1) = -1 (x - 3)
(y - 1) = -x + 3
x + y - 1 - 3 = 0
x + y - 4 = 0
x = -y + 4--------(2)
Substituting (2) into (1), we get
-y + 4 + 10y - 40 = 0
9y - 36 = 0
y = 36/9
y = 4
By applying y = 4 in (1), we get
x = -4 + 4
x = 0
User Roman Bodnarchuk
by
2.1k points
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