When are two triangles said to be in perspective?

a.If the corresponding vertices of two triangles form three lines that intersect in a single point
b.If the corresponding vertices of four triangles form three lines that intersect in a single point

c.If the corresponding vertices of three triangles form three lines that intersect in a single point

d.If the corresponding vertices of two triangles form three lines that intersect in two points.

Question

When are two triangles said to be in perspective?

a.If the corresponding vertices of two triangles form three lines that intersect in a single point
b.If the corresponding vertices of four triangles form three lines that intersect in a single point

c.If the corresponding vertices of three triangles form three lines that intersect in a single point

d.If the corresponding vertices of two triangles form three lines that intersect in two points.

anonymous · Answer

Please help,  a speedy response would be greatly appreciated :)