OpenStudy (anonymous):

Which set of angles shows an obtuse triangle? a) 71, 36, 73 b) 73, 91, 16 c) 90, 64, 26 d) 45, 82, 53

6 years ago
jimthompson5910 (jim_thompson5910):

an obtuse triangle is a triangle that has one angle that is larger than 90 degrees

6 years ago
OpenStudy (anonymous):

but less than 180 right ?

6 years ago
jimthompson5910 (jim_thompson5910):

example: |dw:1345226852284:dw|

6 years ago
jimthompson5910 (jim_thompson5910):

yes, also less than 180

6 years ago
OpenStudy (anonymous):

ohh okay, so I would add them & they would have to be greater than 90 but less than 180?

6 years ago
jimthompson5910 (jim_thompson5910):

no, just a single angle

6 years ago
jimthompson5910 (jim_thompson5910):

if any one angle is greater than 90 but less than 180, then it's part of an obtuse triangle

6 years ago
jimthompson5910 (jim_thompson5910):

you're thinking of adding up the angles to get 180 (which verifies that you have a triangle in general)

6 years ago
OpenStudy (anonymous):

they all equal 180 though

6 years ago
jimthompson5910 (jim_thompson5910):

so they all form triangles, but which ones are obtuse triangles?

6 years ago
OpenStudy (anonymous):

d?

6 years ago
jimthompson5910 (jim_thompson5910):

d) 45, 82, 53 all angles here are less than 90, so this is an acute triangle

6 years ago
OpenStudy (anonymous):

a? @jim_thompson5910

6 years ago
jimthompson5910 (jim_thompson5910):

71 is less than 90 36 is less than 90 73 is less than 90 so all 3 angles are less than 90, so it is an acute triangle

6 years ago
jimthompson5910 (jim_thompson5910):

so choice A is out

6 years ago
OpenStudy (anonymous):

so its B?

6 years ago
jimthompson5910 (jim_thompson5910):

yes, that second angle of 91 is larger than 90 degrees

6 years ago
jimthompson5910 (jim_thompson5910):

so it's an obtuse triangle

6 years ago
OpenStudy (anonymous):

thank you very much

6 years ago
jimthompson5910 (jim_thompson5910):

you're welcome

6 years ago