Sovi.AI - AI Math Tutor

Scan to solve math questions

QUESTION IMAGE

4. regular pentagon qrstu is shown below. segments have been drawn from…

Question

  1. regular pentagon qrstu is shown below. segments have been drawn from each vertex, perpendicular to the opposite side. intersection points are marked as shown. all segments intersect at center point o.

(a) list all angles of rotational symmetry about point o for this pentagon.
(b) what counterclockwise rotation about point o would be needed to map point s onto point q?
(c) what point would each of the following get mapped to if reflected across \\( \overline{q a} \\)?
point c would get mapped to __________ point b would get mapped to __________
(d) if point u is reflected across \\( \overline{d t} \\) and then its image is reflected across \\( \overline{e u} \\), what point would it get mapped onto? justify.
(e) if point t was reflected across \\( \overline{u e} \\) and then rotated clockwise about point o so that it landed in the position it started in, what angle of rotation would be needed? show or explain how you arrived at your answer.
applications

  1. because of the beauty of symmetry, designs are often made that use regular polygons to take advantage of this symmetry. a common shape based on a square is shown below.

(a) draw all lines of symmetry for this design.
(b) what is the minimum angle of rotation needed to map this figure onto itself?
(c) how do the symmetries of this figure compare to those of a simple square?

Explanation:

(a)

Step1: Cálculo del ángulo básico de rotación

Un pentágono regular tiene \(n = 5\) lados. El ángulo de rotación básico es \(\frac{360^{\circ}}{n}\).
$$\frac{360^{\circ}}{5}=72^{\circ}$$

Step2: Enumeración de ángulos de simetría

Los ángulos de simetría de rotación son múltiplos del ángulo básico \(72^{\circ}\) y menores o iguales a \(360^{\circ}\).
$$72^{\circ},144^{\circ},216^{\circ},288^{\circ},360^{\circ}$$

Step1: Cálculo del número de saltos entre \(S\) y \(Q\)

Contando los saltos entre \(S\) y \(Q\) en sentido antihorario: hay \(3\) saltos.

Step2: Cálculo del ángulo de rotación

Como el ángulo básico es \(72^{\circ}\), el ángulo de rotación es \(3\times72^{\circ}\)
$$3\times72^{\circ}=216^{\circ}$$

Step1: Análisis de la reflexión de \(C\)

La reflexión sobre \(\overline{QA}\) mapea \(C\) a \(D\) (por simetría horizontal respecto a \(\overline{QA}\)).

Step2: Análisis de la reflexión de \(B\)

La reflexión sobre \(\overline{QA}\) mapea \(B\) a \(E\) (por simetría horizontal respecto a \(\overline{QA}\)).

Answer:

Los ángulos de rotación son \(72^{\circ},144^{\circ},216^{\circ},288^{\circ},360^{\circ}\)

(b)