Constructions Test - 9

Parallel lines are those lines which do not intersect each other or meet each other in a plane. 

Thus to keep two lines parallel, the perpendicular distance between them is to be kept constant.

Corresponding angles are pair of angles that:

• have distinct vertex points
• lie on same side of transversal
• one angle is interior and other exterior.

When a transversal intersects a pair of lines then 4 such pairs are formed ,

Let a line L interseacts two lines AB and BC thus 8 angles will be formed by the transversal

∠3 = ∠6 (alternate angles)

∠4 = ∠5 (alternate angles)

Hence two pairs of alternate angle are formed.

A ruler and a set square can be used to draw parallel lines as described below:

STEP 1: Position an edge of the set square against the ruler and draw a line along one of the other edges.

STEP 2: Slide the set square into new position while keeping the ruler fixed at the same position.

STEP 3: Draw the line along the same edge as in Step 1.

The two lines thus drawn are parallel to each other.

The tumps of a cricket match are so arranged that the perpendicular distance between the stumps are equal at every point. Hence, the stumps are parallel lines.

As the sum of the interior angles of a triangle should be 180⁰ and in this case 65⁰+85⁰+30⁰ = 180⁰ so this set of measures form a triangle.

As the triangle have 3 sides, so it divide the plane into three parts.

As we know that, the sum of interior angles of a triangle should be always equal to 180⁰ but here 90⁰ + 90⁰ + 10⁰ = 190⁰ > 18⁰, so, we cannot construct this triangle.

To construct a triangle whose three sides are given, the sum of the two sides must always be greater than the third side. As in this case,

(7+5)>3; (3+5)>7; (3+7)>5;

So, we can construct this triangle.