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Mathematics
Mathematics
Problem
Let
r
r
r
be the radius of the circle, which touches x-axis at point
(
a
,
0
)
(a, 0)
(
a
,
0
)
,
a
<
0
a < 0
a
<
0
and the parabola
y
2
=
9
x
y^2 = 9x
y
2
=
9
x
at the point
(
4
,
6
)
(4, 6)
(
4
,
6
)
. Then
r
r
r
is equal to _____
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