Shapes

A. 3 ✓
A triangle is defined as a polygon with exactly three sides and three angles. The word "triangle" literally means "three angles."

B. 2 ✗
A shape with two sides cannot close to form a complete figure.

C. 1 ✗
A single side is just a line, not a shape.

D. 4 ✗
A shape with four sides is a quadrilateral, not a triangle.

Circle (A) is correct because it has a curved edge with no corners or straight sides—that's what "round" means.

• Square has four equal straight sides and corners—not round.
• Rectangle has four straight sides and corners—not round.
• Triangle has three straight sides and pointed corners—not round.

A. 4 is correct. A square is a four-sided shape, and each side meets at a corner (also called a vertex). So a square always has exactly 4 corners—one at each angle.

Why the others are wrong:
- B. 3 — That's a triangle, not a square.
- C. 2 — No basic shape has only 2 corners.
- D. 1 — A circle has no corners; a single corner doesn't describe any standard shape.

Why A is correct:
Stop signs are octagonal (8-sided polygons). This unique shape makes them instantly recognizable and distinguishes them from all other road signs.

Why the others are wrong:
- B (Circle): Circles are used for regulatory signs like "no entry," not stop signs.
- C (Triangle): Triangles are used for warning signs in many countries, not stop signs.
- D (Square): Squares/rectangles are used for informational signs like speed limits and directions, not stop signs.

Correct Answer: A. Square

A square has 4 sides that are all exactly the same length, which is what the question asks for.

Why the others are wrong:
- Rectangle: Has 4 sides, but only opposite sides are equal—not all 4 sides.
- Triangle: Only has 3 sides, not 4.
- Circle: Has no straight sides at all.

A. 6 ✓

The word "hexagon" comes from "hex" (meaning six) + "gon" (meaning sides). A hexagon is a polygon with exactly 6 sides and 6 angles.

Why the others are wrong:
- B. 3 — That's a triangle
- C. 2 — No polygon has only 2 sides
- D. 1 — That's a line, not a polygon

# Explanation

Why A (Rectangle) is correct:
A rectangle has four sides with two pairs of equal opposite sides and four right angles. This window matches that definition.

Why the others are wrong:
- B (Square): A square is a special rectangle where ALL four sides are equal length. This window's sides aren't all the same length.
- C (Circle): A circle is round with no straight edges or corners. This window clearly has straight sides.
- D (Triangle): A triangle has only three sides. This window has four.

Why Circle is correct:
A polygon must have straight sides and vertices (corners). A circle is curved with no straight edges or corners, so it doesn't meet the definition.

Why the others are wrong:
- Square: Has 4 straight sides and 4 corners—it's a polygon
- Rectangle: Has 4 straight sides and 4 corners—it's a polygon
- Triangle: Has 3 straight sides and 3 corners—it's a polygon

Pentagon (A) ✓
- A pentagon has exactly 5 sides. The prefix "penta-" means 5.

Why the others are wrong:
- Square (B): Has 4 sides
- Hexagon (C): Has 6 sides (prefix "hexa-" = 6)
- Octagon (D): Has 8 sides (prefix "octa-" = 8)

A. Triangle ✓

A pizza slice is a triangle because it has three sides: two straight edges that meet at a point in the center of the pizza, and one curved edge around the crust.

Why the others are wrong:
- B. Square – Has four equal sides and right angles; pizza slices don't have this shape
- C. Rectangle – Also has four sides; doesn't match a slice's pointed center
- D. Hexagon – Has six sides; pizza slices only have three