isosceles triangle
Yes under certain dimensional conditions.
An acute triangle can be an isosceles triangle, but it doesn't have to be. An isosceles triangle can be an acute triangle, but it doesn't have to be.
A right triangle and an isosceles triangle have the fact that they are both triangles in common. A right triangle can also be an isosceles triangle.
You cannot. An isosceles triangle cannot be scalene and a scalene triangle cannot be isosceles. So an isosceles scalene triangle cannot exist.
Yes
isosceles triangle
No. An isosceles trapezium (isosceles triangle with its apex removed) would have congruent diagonals but it is not a parallelogram.
Yes under certain dimensional conditions.
An acute triangle can be an isosceles triangle, but it doesn't have to be. An isosceles triangle can be an acute triangle, but it doesn't have to be.
It depends. Strictly speaking, a semi-regular tessellation uses two (or more) regular polygons and, since neither an isosceles triangle nor a parallelogram is regular, it cannot be a semi-regular tessellation. However, a less strict definition allows non-regular components.
isosceles triangle
Circle, ellipse, rectangle, square, parallelogram, rhombus, trapezoid, isosceles triangle, equilateral triangle, any regular polygon.
No
No.
No.
A right triangle and an isosceles triangle have the fact that they are both triangles in common. A right triangle can also be an isosceles triangle.