7)
This triangle has two congruent sides, therefore it is an isosceles triangle.
Also, it has all angles smaller than 90° (acute angles), therefore it is an acute triangle.
8)
All three sides with different lengths, so it's a scalene triangle.
One angle is a right angle (the third angle is equal 180-30-60=90°), so it's an right triangle.
9)
All three sides are congruent, so it's an equilateral triangle.
All three angles are acute, so it's an acute triangle.
10)
All three sides with different lengths, so it's a scalene triangle.
One angle is greater than 90° (obtuse angle), so it's an obtuse triangle
11)
This triangle has two congruent sides, therefore it is an isosceles triangle.
Since the two base angles are 40°, the third angle is equal 180-40-40=100°, therefore the triangle is obtuse.
12)
All three sides with different lengths, so it's a scalene triangle.
All three angles are acute, so it's an acute triangle.