COORDINATE GEOMETRY
10
20
30
40
50
60
70
80
90
100
1
2
3
4
5
6
7
8
9
10
AD
Sol.
=
100
×
1
=
100
1
4
A
B
C
D
G
R
Q.
×
100
=
25
1
4
th
the distance AD =
1
5
×
100
=
20
1
5
th
the distance AD =
(2, 25)
(8, 20)
Sol.
G
=
(2,
25),
∴
GR
=
(8
–
2)
2
+
(20
2
–
25)
x1 = 2,
y1 = 25
x2 = 8,
y2 = 20
R
=
(8,
20)
=
(6)
2
+
(–5)
2
=
36
+
25
=
61 m
Point B is the midpoint of G (2, 25) and R (8, 20)
Let
Coordinates of B = (x, y)
Which is the formula to find length of GR?
+
–
–
(
)
(
)
x2
x1
y2
y1
2
2
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100
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A
B
C
D
G
R
Q.
(2, 25)
(8, 20)
Let the co-ordinates of G be (x1, y1)
Let the co-ordinates of R be (x2, y2)
Let the coordinates of B be (x, y)
B
(x, y)
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A
B
C
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G
R
By Midpoint Formula,
Which formula is used to find co-ordinates of midpoint of a segment
G(2, 25)
R(8, 20)
x1 = 2,
x2 = 8,
x
=
x1
+
x2
2
∴
x
=
2
2
+
8
∴
x
=
10
2
∴
x
=
5
Mid-Point Formula
,
+
x1
x2
2
+
y1
y2
2
5
Sol.
y1 = 25
y2 = 20
Q.
(2, 25)
(8, 20)
B
(x, y)
∴
y
=
y1
+
y2
2
∴
y
=
25
2
+
20
∴
y
=
45
2
∴
y
=
22.5
∴
B
=
(5, 22.5)
10
20
30
40
50
60
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80
90
100
1
2
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A
B
C
D
G
R
It means that the blue flag is in the 5th line and
at a distance of 22.5m along the direction
parallel to AD.
Q.
(2, 25)
(8, 20)
G(2, 25)
R(8, 20)
x1 = 2,
x2 = 8,
Sol.
y2 = 20
y1 = 25
B
(x, y)