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Answer:
B, D
Step-by-step explanation:
Add the two shortest side lengths. For a triangle, the sum must exceed the longest side length.
a. 2.3 +3.7 = 6.0 > 5.1 . . . is a triangle
b. 3 + 11 = 14 < 18 . . . not a triangle
c. 7 + 9 = 16 > 15 . . . is a triangle
d. 8 + 8 = 16 = 16 . . . a "triangle" with 0 area, usually considered <em>not a triangle</em>
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<em>Additional comment</em>
The <em>triangle inequality</em> is written different ways by different authors. They disagree whether the "equal to" case should be considered to be a triangle. That, you might have either of ...
- a + b > c . . . . . used here
- a + b ≥ c
As we have said for the last selection, if the "triangle" is made of line segments that just touch end-to-end, it will have zero area, and will look like a straight line segment of the same length as the longest side. Many authors do not consider this to be a triangle.
