Question

1. which regular polygon can completely tessellate a plane?○ a regular hexagon○ a regular octagon○ a kite○ a scalene triangle

Explanation:

A regular polygon can tessellate a plane if its interior angle divides evenly into 360°.

1. For a regular hexagon: Interior angle = $\frac{(6-2)\times180^\circ}{6}=120^\circ$. $360^\circ \div 120^\circ=3$, so 3 hexagons fit perfectly at a vertex without gaps.
2. For a regular octagon: Interior angle = $\frac{(8-2)\times180^\circ}{8}=135^\circ$. $360^\circ \div 135^\circ \approx 2.67$, which is not an integer, so it cannot tessellate alone.
3. A kite is not a regular polygon, and a scalene triangle is not regular, so they do not meet the "regular polygon" requirement.

Answer:

a regular hexagon