Question

Find area of triangle whose vertices are (1,2),(-6,1),(0,8)

Answer 1

Step-by-step explanation:

Area of triangle=

2

1

[x

1

(y

2

−y

3

)+x

2

(y

3

−y

1

)+x

3

(y

1

−y

2

)]

Here (x

1

,y

1

)=(2,3)

(x

2

,y

2

)=(−1,0)

(x

3

,y

3

)=(2,−4)

=

2

1

[2(0+4)−1(−4−3)+2(3−0)]

=

2

1

[8+7+6]

=

2

21

sq.unit

(i) Let A(−5,1), B(3,−5) and C(5,2) are the vertices of △ABC

Area of triangle=

2

1

[x

1

(y

2

−y

3

)+x

2

(y

3

−y

1

)+x

3

(y

1

−y

2

)]

Here (x

1

,y

1

)=(−5,−1)

=(x

2

,y

2

)=(3,−5)

=(x

3

,y

3

)=(5,2)

=

2

1

[−5(−5−2)+3(2+1)+5(−1+5)]

=

2

1

[35+9+20]

=

2

64

=32 sq.unit