AntonioGalindo
ScottTargetTestPrep
GK_Gmat
Which of the following lists the number of points at which a circle can intersect a triangle?
A. 2 and 6 only
B. 2, 4 and 6 only
C. 1, 2, 3 and 6 only
D. 1, 2, 3, 4 and 6 only
E. 1, 2, 3, 4, 5 and 6 only
Solution:A circle can intersect a triangle at 1 to 6 points, inclusively (see diagrams below):
Attachment:
circles triangles.png
(Note: Technically, 0 should be included in choice E since a circle and a triangle don’t need to intersect each other.)
Answer: E ScottTargetTestPrep,
Bunuel, is there a limit of intersection points between a circle and a triangle? Could there be 7, for example?
Thanks in advance for your help.
AntonioGalindoHow many times can any straight line intersect a circle? Zero, one, or two.
How many straight line (segment)s are there in a triangle? Three.
So, the most we could have is 2*3 = 6.
In order to get to 7, you'd need at least one of the sides of the triangle to intersect the circle three times. Not gonna happen!
For this question, I'm surprised to see so many solutions showing all the options. Each of the answer choices has 2 and 6, so we know we don't need to test/prove those.
Can we do 1? Yep. A and B are out (and note that we don't need to test 3, either).
Can we do 4? Yep. C is out.
Can we do 5? Yep. D is out.
Answer choice E.