Fermi
·
Concept Library
·
Courses
·
Books
·
Problems
·
Simulations
·
Math Wiki
·
High School
Fermi
›
Problems
Mathematics
Mathematics
Problem
A sphere of constant radius
k
k
k
passes through the origin and meets the axis at
A
,
B
A, B
A
,
B
and
C
C
C
. Prove that the centroid of triangle
A
B
C
ABC
A
B
C
lies on the sphere
9
(
x
2
+
y
2
+
z
2
)
=
4
k
2
9(x^2 + y^2 + z^2) = 4k^2
9
(
x
2
+
y
2
+
z
2
)
=
4
k
2
.
Browse the problem library