1. What are two congruent triangles?

Congruent triangles are exactly the same shape and size.

2. Is the smallest angle of a triangle always opposite the shortest side?

Yes, and the biggest angle is always opposite the longest side.

3. Can a triangle be both ISOSCELES and RIGHT-ANGLED?

Yes, its angles would be 90o, 45o and 45o.

4. Can one of the angles in a triangle be bigger than 180 degrees?

Yes. The triangle would be an obtuse-angled triangle.