Question

1. which of the following can tessellate by itself?

a. circle
b. semi - circle
c. equilateral triangle
d. ellipse

Explanation:

• Circle: Circles have curved edges. When placed together, there are gaps between them, so they cannot tessellate by themselves.
• Semi - circle: Semi - circles also have curved edges. Similar to circles, when trying to tile them, there will be spaces left unfilled, so they cannot tessellate alone.
• Equilateral triangle: The interior angle of an equilateral triangle is \(60^{\circ}\). Since \(360\div60 = 6\), we can use 6 equilateral triangles to meet at a point with no gaps. So, equilateral triangles can tessellate by themselves.
• Ellipse: Ellipses have curved and non - congruent (in terms of tiling without gaps) shapes. When we try to place them together, there will be spaces between them, so they cannot tessellate alone.

Answer:

C. Equilateral triangle