(Q5)Let A(x
1
, y
1
) , B(x
2
, y
2
) , C(x
3
, y
3
) be three points. Then find the area of the following triangle and discuss with your friends in groups about the area of that triangle.
X
X'
Y
Y'
A
B
C
(x1,y1)
(x1,y2)
(x2,y2)
AB = (y
2
- y
1
)
BC = (x
1
- x
3
)
A(x
1
,y
1
) = (x
1
,y
1
)
B(x
2
,y
2
) = (x
1
,y
2
)
C(x
3
,y
3
) = (x
3
,y
2
)
Area of △ABC =
1
2
×base×height
△ =
1
2
×b×h =
1
2
×BC×AB
=
1
2
|(x
1
-
3
)×(y
2
-
1
)|
=
1
2
|x
1
(y
2
-
1
) -
3
(y
2
-
1
)|sq.u
Clear