Olympiad Test: Basic Geometrical Ideas - Class 6 MCQ

A point is used to indicate an exact location in space. It has no length, width, or height, meaning it has no size.

Key characteristics of a point include:

• A point is represented by a capital letter, such as A, B, or C.
• It is often depicted as a tiny dot on paper, which can be made thinner with a sharper pencil tip.
• In geometry, a point serves as a fundamental concept for defining other shapes.

Examples of points in everyday life:

• The tip of a compass.
• The sharpened end of a pencil.
• The pointed end of a needle.

A set of points that extends infinitely in both directions is called a line. Key characteristics include:

• A line has no endpoints, unlike a line segment.
• It continues indefinitely in both directions.
• A line can be represented by two points, such as AB, or by a single letter.

In summary, a line is a fundamental concept in geometry, essential for understanding various geometric principles.

The set of points that forms a part of a line with two endpoints is known as a line segment. Key characteristics include:

• A line segment has a definite length.
• It is defined by its two endpoints.
• It can be represented as AB or BA, where A and B are the endpoints.

For example, if you take a thin thread and hold its two ends, stretching it without slack, it visually represents a line segment.

The symbol for a line is ↔.

Therefore, a line PQ is symbolically represented as:

To symbolically represent a line segment between two points, we use the notation AB.

Here are some key points to understand:

• The line segment connects two points, A and B.
• It includes both endpoints, which are essential for defining the segment.
• In diagrams, the line segment is often depicted as a straight line with endpoints marked.

For example, if you have points A and B, the line segment can be represented as:

This notation is a standard way to express line segments in geometry.

A ray is a part of a line that starts at a specific point and extends infinitely in one direction. Here are the key features of a ray:

• The starting point is known as the initial point.
• A ray has no endpoint; it continues indefinitely.
• For example, if we denote a ray as OP, it begins at point O and passes through point P.

In the context of the question, the correct representation of the ray OP is shown in option C. This is because:

• It clearly illustrates the starting point O and the direction it extends towards point P.
• The other options do not accurately depict the characteristics of a ray.

Explanation: In geometry, points are represented using capital letters from the alphabet. For example:

• A point can be labelled as A, B, or C.
• These points are read as point A, point B, and point C.

To illustrate:

• Mark four points on paper and name them A, C, P, and H.
• Identify at least five situations in daily life that represent points, such as stars in the sky.

In summary:

• A point determines a location.
• It is usually denoted by a single capital letter.

Correct option is A.

A line has no end points because it extends infinitely in both directions.

In summary:

• A line is defined as having no end points.
• It stretches endlessly in opposite directions.

Sets of points that extend infinitely in all directions on the same flat surface are known as a plane.

Infinite lines can be drawn through a single point.

This is because:

• A line extends indefinitely in both directions.
• Any direction from the point can form a line.
• Thus, there are countless lines possible through that point.

In summary, through one point, you can draw an infinite number of lines.

Only one line can be drawn through two distinct points in a plane.

This is because:

• A line is defined as extending infinitely in both directions.
• Two points are sufficient to determine a unique line.
• We say that two points determine a line.

In summary, regardless of the position of the points, only one straight line can connect them.

The points P, Q, R, S, T ... lying on line ℓ are said to be collinear.
NOTE: Infinite number of points lying on same line are considered as collinear.

If the lines p, q, r, and s are said to be concurrent, they pass through the same point.

This means:

• All four lines meet at a single location.
• This point is where they intersect.
• It is not possible for them to pass through different points.

In summary, concurrent lines are defined by their intersection at one common point.

Point of concurrence:

When multiple lines meet at a single location, that point is known as the point of concurrence. Here are some key details:

• A point of concurrence is where more than two lines intersect.
• This concept is essential in geometry for understanding how lines relate to each other.
• Identifying such points helps in solving various geometric problems.

Concurrent lines are three or more lines meeting at a point. Intersecting lines are two lines that meet at a common point. The point at which these three lines meet each other is called as the point of concurrency. The point at which these two lines meet each other is called as the point of intersection

In the given figure:

• Points P, O, and Q are called non-collinear points.

Explanation:

• Non-collinear points do not lie on the same straight line.
• In the provided figure, points P, O, and Q are not on a single line; therefore, they are non-collinear.

This distinction is important in geometry as collinearity indicates whether points lie on the same line.

The problem requires filling in the blank for the equation AC = AD - _______, given points A, B, C, and D on a line.

This equation expresses the length of segment AC in terms of AD and another segment.

From the diagram:

• AD represents the total length from point A to point D.
• AC is the length from A to C.

The difference between AD and AC gives the length of segment CD, which is the part of AD extending beyond C to D.

Thus, the correct answer is: DC.

A divider is a tool used to compare line segments effectively.

• It has two pointed ends.
• By placing one point on the end of one segment and the other on the end of another, you can easily see which is longer.
• This tool is particularly useful in geometry for measuring and comparing lengths.

A protractor is used to measure angles, not to construct a line segment. The other instruments, such as:

• Divider
• Compass
• Scale

are all used for constructing line segments.