"Congruent" means "same shape and size as the other one". So one thing all by itself is never congruent. It needs something else to be congruent with. An isosceles triangle is never congruent to a scalene triangle, sometimes congruent to any other kind of triangle, and always congruent to another isosceles triangle that's congruent to the first one.
An isosceles triangle.
Isosceles triangle
Similar, YES. Congruent, NO.
Not always
An obtuse triangle does not always have three congruent sides. An obtuse triangle can be any form that always has three angles.
"Congruent" means "same shape and size as the other one". So one thing all by itself is never congruent. It needs something else to be congruent with. An isosceles triangle is never congruent to a scalene triangle, sometimes congruent to any other kind of triangle, and always congruent to another isosceles triangle that's congruent to the first one.
scalene triangle
An isosceles triangle.
Isosceles triangle
No. A triangle with 2-inch sides is not congruent with a triangle with 3-inch sides.
Not all the time but it can happen
always
Similar, YES. Congruent, NO.
Not always
No.
triangle