What is the orthocenter of a triangle with corners at (4 ,1 ), (7 ,4 ), and (3 ,6 )#?

3 Answers
Feb 10, 2016

The trick to this little problem is to find the slope between two points from there find the slope of perpendicular line which simply given by:
1) m_(perp) = -1/m_("original") then
2) find the equation of line that passes through the angle opposite the original line for you case give: A(4,1), B(7, 4) and C(3,6)
step1:
Find the slope of bar(AB) => m_(bar(AB))
m_(bar(AB)) = (4-1)/(7-4) = 3 :. m_(perp) = m_(bar(CD)) = -1/1 = -1
To get the equation of line write:
y = m_bar(CD)x + b_bar(CD); use point C(3, 6) to determine barB
6 = -3 + b_bar(CD); b_bar(CD) = 9 :.
y_bar(CD) = color(red)(-x + 9) color(red)" Eq. (1)"

step2
Find the slope of bar(CB) => m_(bar(CB))
m_(bar(AB)) = (6-4)/(3-7) = -1/2 :. m_(perp) = m_(bar(AE)) = 2
To get the equation of line write:
y = m_bar(AE)x + b_bar(AE); use point A(4, 1) to determine barB
1 = 8 + b_bar(AE); b_bar(CD) = -7 :.
y_bar(AE) = color(blue)(2x - 7) color(blue)" Eq. (2)"
Now equate color(red)" Eq. (1)" = color(blue)" Eq. (2)"
Solve for => x = 16/3
Insert x=2/3 into color(red)" Eq. (1)"
y = -2/3 + 9 = 11/3

enter image source here

Feb 10, 2016

The trick to this little problem is to find the slope between two points from there find the slope of perpendicular line which simply given by:
1) m_(perp) = -1/m_("original") then
2) find the equation of line that passes through the angle opposite the original line for you case give: A(4,1), B(7, 4) and C(3,6)
step1:
Find the slope of bar(AB) => m_(bar(AB))
m_(bar(AB)) = (4-1)/(7-4) = 3 :. m_(perp) = m_(bar(CD)) = -1/1 = -1
To get the equation of line write:
y = m_bar(CD)x + b_bar(CD); use point C(3, 6) to determine barB
6 = -3 + b_bar(CD); b_bar(CD) = 9 :.
y_bar(CD) = color(red)(-x + 9) color(red)" Eq. (1)"
step2
Find the slope of bar(CB) => m_(bar(CB))
m_(bar(AB)) = (6-4)/(3-7) = -1/2 :. m_(perp) = m_(bar(AE)) = 2
To get the equation of line write:
y = m_bar(AE)x + b_bar(AE); use point A(4, 1) to determine barB
1 = 8 + b_bar(AE); b_bar(CD) = -7 :.
y_bar(AE) = color(blue)(2x - 7) color(blue)" Eq. (2)"
Now equate color(red)" Eq. (1)" = color(blue)" Eq. (2)"
Solve for => x = 16/3
Insert x=2/3 into color(red)" Eq. (1)"
y = -2/3 + 9 = 11/3

enter image source here

Feb 10, 2016

Orthocenter(16/2, 11/3)

Explanation:

The trick to this little problem is to find the slope between two points from there find the slope of perpendicular line which simply given by:
1) m_(perp) = -1/m_("original") then
2) find the equation of line that passes through the angle opposite the original line for you case give: A(4,1), B(7, 4) and C(3,6)
step1:
Find the slope of bar(AB) => m_(bar(AB))
m_(bar(AB)) = (4-1)/(7-4) = 3 :. m_(perp) = m_(bar(CD)) = -1/1 = -1
To get the equation of line write:
y = m_bar(CD)x + b_bar(CD); use point C(3, 6) to determine barB
6 = -3 + b_bar(CD); b_bar(CD) = 9 :.
y_bar(CD) = color(red)(-x + 9) color(red)" Eq. (1)"
step2
Find the slope of bar(CB) => m_(bar(CB))
m_(bar(AB)) = (6-4)/(3-7) = -1/2 :. m_(perp) = m_(bar(AE)) = 2
To get the equation of line write:
y = m_bar(AE)x + b_bar(AE); use point A(4, 1) to determine barB
1 = 8 + b_bar(AE); b_bar(CD) = -7 :.
y_bar(AE) = color(blue)(2x - 7) color(blue)" Eq. (2)"
Now equate color(red)" Eq. (1)" = color(blue)" Eq. (2)"
Solve for => x = 16/3
Insert x=2/3 into color(red)" Eq. (1)"
y = -2/3 + 9 = 11/3

enter image source here