The plane x + 2y + 3z = 6 contains the points
A(6,0,0); B(0,3,0); and C(0,0,2).
The center of the circle circumscribing the points will be the intersection of the bisecting planes of the sides of the triangle with the plane of the triangle.
AB
vector AB = <-6, 3, 0> or <2, -1, 0>
midpoint M(3, 3/2, 0)
Bisecting plane
2(x - 3) - (y - 3/2) = 0
2x - 6 - y + 3/2 = 0
4x - 12 - 2y + 3 = 0
4x - 2y = 9
AC
vector AC = <-6, 0, 2> or <3, 0, -1>
midpoint M(3, 0, 1)
Bisecting plane
3(x - 3) - 1(z - 1) = 0
3x - 9 - z + 1 = 0
3x - z = 8
The center of the circle is the intersection of the three planes:
x + 2y + 3z = 6
4x - 2y = 9
3x - z = 8
Center (h, k, p) = (39/14, 15/14, 5/14)
r = radius
r² = (39/14 - 6)² + (15/14)² + (5/14)² = 2275/196
r = √(2275/196) = 5√91 / 14 ≈ 3.4069
The circumcircle of the points A, B, and C is the intersection of the plane
x + 2y + 3z = 6
with the sphere
(x - h)² + (y - k)² + (z - p)² = r²
(x - 39/14)² + (y - 15/14)² + (z - 5/14)² = 2275 / 196
2007-10-25 22:56:43
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answer #1
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answered by Northstar 7
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x=6
y=3
z=2
gravity center is the center of the circle
(Hint: divide the sum by 3)
Circle equation(x-x1)^2+(y-y1)^2=r^2
satisy A,B,C points
2007-10-25 04:37:58
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answer #2
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answered by iyiogrenci 6
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