Math Is Fun Forum

taylorcrue

Guest

geometry

Guys I really need help on these questions!!! I just don't understand what to do to figure them out.
7. Each set of numbers below represents the lengths of three line segments.
Which set represent line segments that could be connected to form a triangle? Give the reasoning or show your work to support your choice:
A. (1, 2, 3)
B. (3, 4, 5)
C.(1, 10, 100)
D. (1, 2, 5)
E. (1, 3, 4)
F. (1, 20, 100)

8. Each set of numbers below represents the lengths of three line segments.
Which set represent line segments that could be connected to form a triangle? Give the reasoning or show your work to support your choice
A. (3, 5, 7)
B. (3, 4, 8)
C.(1, 4, 6)
D. (1, 3, 5)
E. (5, 6, 11)
F. (1, 10, 20)

9. Each set of numbers below represents the lengths of three line segments.
Which set represent line segments that could be connected to form a triangle?  Give the reasoning or show your work to support your choice
A. (2, 2, 5)
B. (5, 4, 1)
C.(5, 10, 15)
D. (7, 10, 16)
E. (2, 3, 5)
F. (5, 10, 25)

Grantingriver

Member

Registered: 2016-02-01

Posts: 129

Re: geometry

It is very simple. You have to use the "strict' triangle inequality which states that the sum of the lengths of any two sides of a triangle is greater then the length of the other side or more precisely if x, y and z are the lengths of the sides of a given triangle then:

Therefore the solutions are:
1-B
2-A
3-D
I hope that answers your question.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,855

Re: geometry

Hi taylorcrue,

Remember, the triangle inequality theorem states that the sum of any two sides of a triangle must be greater than the length of the third side.

In #7, only B would be appropriate.

Use the same analogy.

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