This is a right triangle, because it has one right angle.
This is an obtuse triangle, because it has one angle more than 90 degrees
This is an acute triangle, it has all angles are from 1 degrees to 89 degrees.
This is an isosceles triangle, when i see this it reminded me of ice cream cone and pizza and even a pent. 2 sides and 2 angles are the same.
This is an equilateral triangle, all sides and all angles are the same.
This is a scalene triangle, all sides and angles are different.