Question

which statement describes the order of rotational symmetry for an isosceles triangle? an isosceles triangle has an order 0 rotational symmetry because there is no angle at which it can be rotated onto itself. an isosceles triangle has an order 1 rotational symmetry because it does not have all congruent angles. an isosceles triangle has an order 2 rotational symmetry because it has 1 pair of congruent angles. an isosceles triangle has an order 3 rotational symmetry because it has 3 angles.

Explanation:

Step1: Define order of rotational symmetry

The order of rotational symmetry of a shape is the number of times it can be rotated around a central point and still look the same. A full - rotation is 360°. For a non - regular polygon like an isosceles triangle, the only angle of rotation that maps it onto itself is 360° (a full - turn).

Step2: Determine the order

When we consider the angles of rotation for an isosceles triangle, other than a 360° rotation, no other rotation (less than 360°) will map the triangle onto itself. When we rotate a shape by 360°, we say the order of rotational symmetry is 1.

Answer:

An isosceles triangle has an order 1 rotational symmetry because it does not have all congruent angles.