60 POINTS! AKA, ALL MY POINTS. HELP ME PLEASE, DUE TODAY. COUNTS AS A GRADE, THANK YOU ! <3

see below

Step-by-step explanation:

1. If one of the angles is 140 degrees, that is greater than 90 degrees, which makes it obtuse

Two of the sides are equal, which makes it isosceles

The triangle is isosceles obtuse

2.  All triangles are plane figures  true because they are 2 dimensional.

   All triangles have 3 angles.   true Triangles have 3 sides and 3 angles

  All triangles have 3 straight sides. true Triangles have 3 sides and 3 angles

False,  triangles do not have to have a right angle

False,  all triangles are polygons.  They are 3 sided closed figures

3.  To be an acute triangle, all angles must be acute

  exactly three acute angles - true

 polygon  - true  

 exactly one acute angle - false (they all must be acute)

exactly 2 acute angles  false ( they all must be acute)

one right angle  false (they all must be acute)

3 straight sides true  Triangles have 3 sides and 3 angles

1) Obtuse isosceles

One angle > 90, so obtuse

2 congruent angles, so isosceles

2) First three are correct.

Last two incorrect because not all triangles are right angle triangles.

And every triangle is a 3-sided polygon

3) First, second and last statements are correct.

Since it's an acute triangle, all 3 angles should be acute