Question

find the area of the triangle whose vertices are (2,8) (-1,0) (2,-8)

Answer 1

area = 1/2 bh
b= 16 units , h= 3 units 
area = 24 unit square

Answer 2

"Area of triangle is 24 sq.units.

Given:

Vertices are (2,8) (-1,0) (2,-8)

To find:

Area of triangle.

Solution:

A(2,8); B( - 1,0); C(2, - 8)

$x_1 = 2; y_1 = 8$

$x_2 = -1; y_2 = 0$

$x_3 = 2; y_3 = -8$

$Area\quad of\quad triangle\quad =\quad \frac { 1 }{ 2 } \left[ { { x }_{ 1 }({ y }_{ 2 }-{ y }_{ 3 })\quad +\quad { x }_{ 2 }({ y }_{ 3 }-{ y }_{ 1 })\quad +\quad { x }_{ 3 }({ y }_{ 1 }-{ y }_{ 2 }) } \right]$

$=\quad \frac { 1 }{ 2 } \quad \left[ { 2(0-(-8))\quad +\quad (-1)(-8-8)\quad +\quad 2(8-0) } \right]$

$=\quad \frac { 1 }{ 2 } \quad \left[ { 16+(+16)+16 } \right]$

$=\quad \frac { 1 }{ 2 } \quad \times \quad 48$

Area of triangle = 24 sq.units"