<span>The radius of a sphere join refers to the (D) the center and a point on the sphere. A radius is the distance of the center point to any sides of the circle or sphere. The point on the sphere can be anywhere. The center and a point on the sphere forms a sphere join.</span>
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The shape of the cross section is a triangle. Therefore, the answer is the second option: Triangle.
A rectangular pyramid is a pyramid that has a rectangle as its base. Therefore, its base has four sides. The rectangular pyramid also has four triangles that coming together in its apex. So, if the rectangular pyramid is<span> sliced so the cross section is perpendicular to its base and passes through its vertex, the cross section obtained is a triangle.</span>