Plane Geometrical Construction MCQ Quiz in বাংলা - Objective Question with Answer for Plane Geometrical Construction - বিনামূল্যে ডাউনলোড করুন [PDF]

Explanation:

A circle is a 2D figure because it lies entirely in a two-dimensional plane and is defined by its radius. It has no height or depth.
Additional InformationCube: A 3D shape with six square faces.

Sphere: A 3D solid with all points equidistant from the center.

Cylinder: A 3D solid with two circular bases connected by a curved surface.

Explanation:

Cylinder, Cone, and Sphere are 3D solids because they have length, width, and height and occupy physical space.

Additional InformationCylinder: Has circular bases and a curved surface.

Cone: Has a circular base and tapers to a point.

Sphere: A perfectly round 3D shape, like a ball.

Square: Is a 2D shape because it only has length and width, with no depth or volume.

Explanation:

2D Solids:

• Objects that lie in a two-dimensional plane and have only length and width (e.g., square, rectangle, circle). They do not have depth or height.

3D Solids:

• Objects that occupy space and have three dimensions: length, width, and height (e.g., cube, sphere, cylinder).

A practical example:
A rectangle is 2D with length and width only.
A box (cuboid) is 3D with length, width, and height.

Explanation:

A polyhedron is a 3-dimensional solid figure with flat polygonal faces, straight edges, and vertices.

Let’s analyze the options:

1. Tetrahedron: A polyhedron with 4 triangular faces.

2. Cube: A polyhedron with 6 square faces.

3. Square Pyramid: A polyhedron with a square base and 4 triangular faces meeting at a point.

4. Cone: Not a polyhedron because it has a curved surface and does not consist of flat polygonal faces.

Explanation:

Rhombus:

A quadrilateral whose opposite sides are parallel and equal but not right angles. In a rhombus 4 sides are equal.

Additional Information

Trapezium:

A quadrilateral has only two opposite sides parallel and the other two sides are not parallel.

Rectangle:

It is a special case of a parallelogram whose opposite sides are parallel and equal and the angles are right angles.

Explanation:

In a rectangle, all four angles are right angles

Additional InformationOther properties of rectangles are as follows:

Diagonals:

• The diagonals of a rectangle are equal in length and bisect each other at a right angle.
• This means that the diagonals divide the rectangle into four congruent right-angled triangles.

Symmetry:

• Rectangles have at least two lines of symmetry.
• The center of the rectangle is the point of intersection for these lines of symmetry.

Equal opposite sides:

• Adjacent sides of a rectangle are equal in length.
• This property is a consequence of the opposite sides being equal and parallel.

Perimeter:

• The perimeter of a rectangle is calculated by adding the lengths of all four sides.

Area:

• The area of a rectangle is calculated by multiplying the length and width.

Explanation:

Quadrilateral has 4 sides and angles.

Additional Information

Quadrilaterals

• Square- All sides equal and all angles right angles.
• Rectangle or oblong- Opposite sides equal and all angles right angle.
• Rhombus- All sides are equal, but angles are not right angles.
• Rhomboid- Opposite sides equal and parallel, but angles are not right angles.
• Trapezoid- Only two sides parallel.
• Trapezium- No sides parallel, but may have two of its sides equal. When two of the sides are equal, it is called a trapezium or kite. Polygons: Regular and irregular; when all sides are equal, it is a regular polygon, otherwise irregular.

Explanation:

Octahedron:

• A solid having eight equilateral triangular faces.

Additional InformationTetrahedron: 

• A solid having four equilateral triangular faces solid having least number of flat surfaces. 

Cube or Hexahedron:

• A solid having six regular square faces.

Explanation:

Concept

Sum of exterior angles =\( (2n+4) \times 90 \)

where n = number of sides

Calculation

The figure shows the hexagon 

n = 6

Sum of exterior angles =\( (2 \times 6+4) \times 90 = 1440\)

Explanation:

The quadrilateral if opposite sides are equal and parallel and all four angles are right angles is called a rectangle.

Additional Information Other properties of rectangles are as follows:

Diagonals:

• The diagonals of a rectangle are equal in length and bisect each other at a right angle.
• This means that the diagonals divide the rectangle into four congruent right-angled triangles.

Symmetry:

• Rectangles have at least two lines of symmetry.
• The center of the rectangle is the point of intersection for these lines of symmetry.

Equal opposite sides:

• Adjacent sides of a rectangle are equal in length.
• This property is a consequence of the opposite sides being equal and parallel.

Perimeter:

• The perimeter of a rectangle is calculated by adding the lengths of all four sides.

Area:

• The area of a rectangle is calculated by multiplying the length and width.