# How Many Right Angles Does Each Shape Have?

Triangles can have up to one **right angle**, while quadrilaterals can have up to four. Pentagons can have up to two right angles, and hexagons can have up to one. Heptagons, octagons, nonagons, and decagons can have up to zero, two, one, and zero right angles respectively.

**Right Angles in Different Shapes**

Here is the list with each shape name and how many right angles it has:

### Right Angles In A Rectangle

The rectangle has 4 right angles formed by its perpendicular adjacent sides. The angles inside a rectangle measure 90 degrees, making it a quadrilateral with two sets of parallel sides and 4 right angles.

**Examples: Photo frames, books, doors, windows, beds, tables**

### Right Angles In A Trapezoid

The trapezoid has no right angles since it has no perpendicular or parallel sides. Its sloping sides form 4 angles that do not measure 90 degrees.

But special Trapezoid, Right Trapezoid have two right angles.

**Examples: Corner of a poster frame, edge of a chalkboard, side of a building**

### Right Angles In A Parallelogram

The parallelogram has no right angles between its sloping sides. Its opposite sides are parallel which creates internal angles that do not measure 90 degrees.

### Right Angles In A Square

The square being a regular quadrilateral has 4 identical right angles formed between its equal and perpendicular adjacent sides. All angles inside a square measure 90 degrees.

**Examples: Floor tiles, waffles,CHATGPT windows, quilt patches, graph paper boxes**

### Right Angles In A Triangle

The triangle has no right angles between any of its 3 sides that intersect at corners called vertices, forming only acute and **obtuse angles**.

But right-angles triangle has one interior right angle.

### Right Angles In A Rhombus

The rhombus typically has no right angles since its 4 equal length sides are not perpendicular. The angles can differ depending on shape, not containing 90 degrees.

### Right Angles In A Pentagon

The pentagon as a 5-sided polygon typically does not contain any right angles between its adjacent sides which all differ in length from one another.

### Right Angles In A Quadrilateral

The quadrilateral can have a combination of right angles between its 4 sides depending on if it has perpendicular and parallel sides, but doesn’t necessitate any by default.

Examples: Picture frames with right-angled corners, tabletops, door frames

### Right Angles In A Cube

The geometric 3D cube shape has 8 right angles formed between its square faces and perpendicular edges, making its internal angles all measure 90 degrees.

**Examples: Dice, ice cubes, Rubik’s cubes, boxes**

### Right Angles In A Hexagon

The flat 2D hexagon with its 6 straight sides usually does not have right angles between its adjacent sides, which can differ in length.

### Right Angles In A Polygon

Polygons can have right angles between their multiple straight sides if they contain sets of parallel and perpendicular lines, but don’t require any by default.

**Examples: Stop signs, yielding signs, window panes divided by muntins**

### Right Angles In A Stop sign

The octagonal stop sign by definition has 8 right angles between its straight sides which are alternating long and short. Some real-world examples are the red stop signs at road intersections or on school buses and crossing guard stop paddles.

### Right Angles In An Acute triangle

The acute triangle has angles inside measuring less than 90 degrees due to its lack of parallel or perpendicular sides forming no right angles.

### Right Angles In A Right trapezoid

A right trapezoid is a quadrilateral with two sets of parallel sides forming two right angles between them, while the other two internal angles are **acute**. Examples are the corner of a rectangular table or the side of a hallway with perpendicular adjoining walls.

### Right Angles In A Equilateral triangle

An equilateral triangle lacks any right angles between its equal length sides which join to create 3 acute 60 degree internal angles.

### Right Angles In A Rhombus with congruent diagonals

A rhombus with congruent diagonals bisecting its angles at 90 degrees is a special case called a square which always has 4 identical right angles.

**Examples: Square quilt patches, building foundation, open box lids**

### Right Angles In An Obtuse triangle

The internal angles of an obtuse triangle measure one greater than 90 degrees between its three straight sides with no right angles.

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### Why Is Angle In A Semicircle A Right Angle

In a semicircle, the angle formed by connecting the endpoints of the diameter to any point on the semicircle is a right angle. This is because the diameter bisects the circle into two equal halves, creating two congruent right-angled triangles. In a right-angled triangle, one of the angles is always 90 degrees. Therefore, in a semicircle, the angle subtended by the diameter is a right angle, measuring 90 degrees. This geometric property holds true for any point on the semicircle.

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