Bài giảng Unit 10 Midpoint of a line segment

On the ray Ox, draw two line segments OM and ON so that OM=3cm, ON=6cm. compute the length of MN? Compare OM and MN

REVIEW

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QUESTION

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O٠x٠ ٠M N 3cm

6cm On the ray Ox, we have OM < ON

(3cm<6cm) so that point M is between two points O and N

So we have: OM + MN = ON

3 + MN = 6 => MN = 6 – 3 => MN = 3(cm)

So : MN =3 cm

0

OM = MN

Point M divides line segment ON into 2 congruent parts.

On the ray Ox, draw two line segments OM and ON so that OM=3cm, ON=6cm. Calculate the length of MN? Compare OM and MN

Mr. M, what’s your name?

OM = 3cm MN =3cm

SOLUTION

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The point M of line segment AB is the point which is located between A, B and has the equal distance from A, B.

A midpoint divides a line segment into two congruent segments.

Note: The midpoint of line segment AB is also known as the central point of line segment AB

UNIT 10. UNIT 10. MIDPOINT OF MIDPOINT OF A LINE SEGMENT A LINE SEGMENT

1. DEFINITION

A M B

Point M is midpoint of line

segment AB

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A B M

Fig. 2

A B

M

Fig. 3

B M A

Fig. 1

A

B

M

Fig. 4

M is not between A, B

M is between but not equidistant from A, B

M is equidistant from but not between A, B

M is between and equidistant from A, B

M is not midpoint of line segment AB

APPLY: IN EACH CASE, IS M MIDPOINT OF LINE

SEGMENT AB OR NOT, AND WHY?

M is not midpoint of line segment AB

M is midpoint of line segment AB

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2. HOW TO DRAW THE MIDPOINT OF A LINE SEGMENT?

i) Using straight ruler with measurements For example:

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M N K

Draw midpoint K of segment MN=5cm

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2. HOW TO DRAW THE MIDPOINT OF A LINE SEGMENT?

ii) Folding paper: Make a midpoint on paper

sheet, fold it so that 2 sides overlap to define a midpoint

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