No. An angle cannot be isosceles.
Yes, but only one angle will be obtuse.
They can make an obtuse angle, a straight angle or a reflex angle.
That is an obtuse angle.
Obtuse angle (here is the formula) -: 90° = Right angle and if you don't know the obtuse angle is more than 90° so adding 2 will make it an obtuse angle.
No. It is not possible to make a equilateral triangle that is obtuse.
yes
Yes it is possible. Obtuse means the triangle contains an angle which is greater than 90 degrees, and isosceles means the triangle has two sides of the same length. So to prove this in the easiest way possible, you can make a dot on your page, measure 91 or more degrees and draw two equal length lines out at this angle, then connect these two lines to make an obtuse isosceles triangle.
No.
If it has an obtuse angle
Yes
No, they are not always obtuse, because a scalene triangle can also sometimes be an obtuse triangle (meaning that one interior angle is obtuse), making one exterior angle acute. Scalene triangles also can be a right triangles (meaning that one interior angle is a right angle), which would make an exterior angle a right angle. Then also they can be acute triangles, in this case all 3 exterior angles are obtuse.
No, a triangle can't have more than 1 obtuse angle because all the angles have to equal 180 degrees, and an obtuse angle is larger than 90 degrees. if it had more than 1 obtuse angle, the angles wouldn't equal 180 degrees and you wouldn't be able to make a third angle.