Straight lines Instructions You have to write Do these slides on - - PowerPoint PPT Presentation

• 7. Parallel

Straight lines

You have to write these slides on your mathematics writing book Do Exercise 7.1 Exercise 7.2 Instructions

The two end points of the straight line segment

Stra Straigh ight t lin line se e segm gment ent

The portion AB of the straight line l is defined as the straight line segment AB.

Two straight lines which do not intersect each other are called parallel

Pa Paral rallel lel strai straigh ght t lin lines es

The straight lines p and q do not intersect each other. Due to that the two straight lines p and q are parallel

Two straight lines which do not intersect each other are called parallel

Pa Paral rallel lel strai straigh ght t lin lines es

The straight lines a and b do not intersect each other. Due to that the two straight lines p and q are parallel

a b

To indicate both lines are parallel to each other, arrowheads are drawn on the straight lines in the same direction.

How How ind indica icate both te both lin lines a es are re Pa Paral rallel lel to eac to each othe h other

Sometimes not only the two line but also several lines, we have to indicate as parallel to each other,

at that situation we also drawn arrowheads on the straight lines in the same direction.

The shortest distance from a point to a line define as perpendicular distance between straight line

Pe Perpe rpendic ndicular ular dis distan tance ce

• 1. The perpendicular distance from a

point to a straight line

consider the A point and m straight line segment, A P Q R It have marked several distance between line m and point A m

consider the A point and m straight line segment, AP repesent the shortest dintance between line and point Due to that AP is the perpendicular distance Between line m and point P A P m

The shortest distance from a point to a line define as perpendicular distance between straight line

Pe Perpe rpendic ndicular ular dis distan tance ce

• 2. The perpendicular distance between

two parallel straight line

The perpendicular distances from the two points A and B that lie

• n the line l to the

straight line m are equal to each other. That is, A Q B P m l

AP = BQ

The perpendicular distances from the two points C and D that lie on the line a to the straight line b are unequal to each other. That is, C S D R a b

CR = DS

Write down the names of five objects that can be observed in the classroom that have parallel edges. 1. 2. 3. 4. 5.

Do Exercise 7.1

Drawing parallel lines using a straight edge and a set square

Drawing a straight line parallel to a given straight line using a straight edge and a set square Do Activity 3 from the text book while watching today(2020.04.27) video lesson

Do Activity 4 from the text book while watching today(2020.04.27) video lesson

Dr Drawin awing a g a st straigh raight t li line ne pa parallel rallel to to a a gi give ven n st straig raight ht li line, ne, th thro rough ugh a a po point int wh whic ich is h is no not t

• n
• n th

the st e straig raight ht li line, u ne, using sing a a st straigh raight e t edge dge an and a d a se set sq t squa uare re

Drawing a line parallel to a straight line at a given distance from the straight line, using a ruler and a set square

Do Activity 5 from the text book while watching today(2020.04.27) video lesson

Examining whether two straight lines are parallel

Do Activity 6 from the text book while watching today(2020.04.27) video lesson

Drawing rectilinear plane figures using a set square and a straight edge

Do Activity 7 from the text book while watching today(2020.04.27) video lesson

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