by looking to at it by looking to at it
When it has four sides equal in length and each of the four angles are 90 degrees.
A 45-45-90degree triangle is classified as an isosceles triangle.
A quadrilateral with no right angles can refer to most kites, most trapezoids, some parallelograms, and a few quadrilaterals that cannot be classified any more specifically.
All angles of an octagon must add up to 1080 degrees. A "regular" octagon has all equal angles, which are all 135 degrees. Other angles are possible though. As long as the shape has 8 sides and all angles add up to 1080, it is still classified as an octagon.
sides, and angles
A square is classified as a rectangle with four corner angles.
A square is classified as a quadrilateral because it has four sides and four angles. It is also classified as a regular polygon, as all four sides are equal in length and all four angles are right angles.
A trapezoid can have up to two right, 90 degree angles for it still to be classified as a trapezoid.
A triangle with no equal sides or angles will always be classified as 'scalene'.
by looking to at it by looking to at it
Depends; if it's classified as "regular", then all angles of the polygon are congruent.
A Quadrilateral or a rhombus. A it has fur sides and the angles add up to 360o.
A 67 degree angle would be acute. Acute angles are smaller that 90 degrees. Right angles are 90 degrees. Obtuse angles are more that 90 degrees. Straight angles are 180 degrees.
It depends on how they are classified. They can have 1 to 4 acute angles, they can have 1 to 4 right angles, they can have 1 to 5 obtuse angles. The individual values of the angles will generate different pentagons. They can be regular or irregular. They can be convex or concave.
A square must have 4 parallel sides of equal length and 4 right angles, a rhombus does not need to have any right angles (but can include one or more right angles).
A parallelogram can have 4 right angles, but instead of being classefied as a parallelogram, it will be more specifically classified as a rectangle, but all rectangles are parallelograms.