If the ends of the base of an isosceles triangle are at (2,0) & (0,1) & the eqn of one side is
x=2,
then the orthocentre of the triangle is

a) (3/2, 3/2)
b) (5/4, 1)
c) (3/4, 1)
d) (4/3, 7/12)
...?

Respuesta :

if O is the orthocenter, O=(xo, yo)
such that xo=(2+0 + 2)/3, so xo= 4/3, so the answer must be

d) (4/3, 7/12)

Answer:

The orthocenter of the triangle is [tex](\frac{5}{4},1)[/tex] and option b is correct.

Step-by-step explanation:

The ends of the base of an isosceles triangle are at (2,0) & (0,1).

Orthocentre of the triangle is the intersection point of all three altitudes from its vertices.

First find any two altitudes, then find intersection point of altitudes.

The equation of a side is x=2, which is an vertical line. The opposite vertices of this side is (0,1), so the perpendicular line is a horizontal line. The equation of first altitude is

[tex]y=1[/tex]                              .... (1)

In an isosceles triangle, then attitude is the median of non-equal side. It means the altitude is passing through the midpoint of base side.

[tex]Midpoint=(\frac{2+0}{2},\frac{0+1}{2})=(1,0.5)[/tex]

Slope of base side is

[tex]m_1=\frac{y_2-y_1}{x_2-x_1}=\frac{1-0}{0-2}=-0.5[/tex]

The product of slopes of two perpendicular lines is -1.

[tex]m_1\times m_2=-1[/tex]

[tex]-0.5\times m_2=-1[/tex]

[tex]m_2=2[/tex]

The point slope form of a line is

[tex]y-y_1=m(x-x_1)[/tex]

Where, m is slope.

The slope of second altitude is 2 and it passing through the pint (1,0.5), therefore the equation of second altitude is

[tex]y-0.5=2(x-1)[/tex]

[tex]y=2x-1.5[/tex]                ..... (2)

From equation (1) and (2), we get

[tex]x=\frac{5}{4}[/tex]

[tex]y=1[/tex]

Therefore the orthocenter of the triangle is [tex](\frac{5}{4},1)[/tex] and option b is correct.

Ver imagen DelcieRiveria