NCERT MCQ Solutions for Class 7 Maths Ganita Prakash Chapter 5 Parallel and Intersecting Lines

When two lines intersect, they form four angles at the point of intersection. Each pair of opposite angles is equal. These four angles help identify angle relationships such as vertically opposite angles and linear pairs.

When two lines cross, the angles that do not share a side but lie opposite each other are called vertically opposite angles. These angles are always equal and help in checking angle measurements in geometry.

Parallel lines do not intersect even when extended indefinitely. They remain equidistant at all points. This property is used in construction and design to ensure symmetry and alignment between structures.

A linear pair consists of two adjacent angles on a straight line. The angles together form a straight angle which measures 180°. This fact is used to find unknown angles in geometric problems.

When two lines intersect at right angles (90°), they are said to be perpendicular. Each of the four angles formed is 90°. This is a special case of intersecting lines used widely in geometry.

Alternate interior angles lie on opposite sides of the transversal and inside the two lines. If these angles are equal, it confirms that the lines are parallel. This is a key test of parallelism.

Perpendicular lines intersect in such a way that they create four right angles. Each of these angles measures 90°. This perpendicular relationship is a key feature in geometric constructions like squares and rectangles.

The mathematical symbol for parallel lines is ∥. For example, if line AB is parallel to line CD, we write AB ∥ CD. This notation is used in proofs and descriptions of geometric figures.

When a transversal intersects two lines, four alternate angles are formed—two on each side of the transversal. They help identify whether the lines are parallel based on angle equality.

Linear pairs are adjacent angles on the same line. Their measures always add up to 180°, making them supplementary. This relationship is useful in finding missing angle measures when one angle is known.

When a transversal intersects two parallel lines, the interior angles on the same side add up to 180°. This rule helps verify if two lines are parallel. For example, ∠ADC + ∠BCD = 180°. This property is a key identifier of parallel lines in geometry.

When two lines intersect, they form four angles. The opposite pairs of angles are called vertically opposite angles. These angles are always equal regardless of their measure. For instance, if ∠a = 120°, then its opposite ∠c is also 120° due to their symmetric position.

Parallel lines are lines that never intersect and stay equidistant. If two lines intersect, they meet at a point and cannot be parallel. The other options describe properties of parallel lines such as equal corresponding and alternate angles formed by a transversal.

A transversal is a line that crosses at least two other lines at different points. When it intersects two parallel lines, it forms eight angles, including corresponding, alternate and interior angles. It is a fundamental concept in understanding parallel line relationships.

When two lines intersect and all four angles formed are equal, each angle measures 90°. Such lines are called perpendicular lines. This is because the total angle around a point is 360°, and dividing it equally among four angles gives 90° each.

When a transversal intersects two parallel lines, corresponding angles are formed on the same side of the transversal and in matching corners. These angle pairs are always equal and help identify or prove that lines are parallel using geometric reasoning.

If a transversal intersects two lines and corresponding angles are equal, the two lines must be parallel. This is a property used to verify parallelism between lines. The equality of corresponding angles is both a necessary and sufficient condition for parallelism.

In geometry diagrams, parallel lines are indicated using arrow marks. One arrow mark per line is used for one pair. Two arrows show another distinct pair. This consistent notation visually indicates the relationship and is standard in geometric representations of parallel lines.

When a transversal intersects two lines, eight angles are formed. These include four angles at each point of intersection. The angles include corresponding, alternate interior and vertically opposite angles. These relationships help determine whether the lines intersected are parallel or not.

Linear pairs are adjacent angles formed when two lines intersect. The two angles lie on a straight line and therefore must sum up to 180°. This property helps solve for unknown angles and is used to verify measurements in geometric constructions.