Exercise 27 Page 393

Practice makes perfect

a If three points are collinear, you can say that the middle point is between the other two points.

Since the points

A,

B,

and

C

are on a straight line, and

B

is in the middle, the statement is true.

b Three points are collinear if all of them are on a straight line.

Point $C$ is not on a straight line with $B$ and $E .$ Therefore, the statement is false.

c As we can see in the picture, the points

A,

D,

and

H

are on a straight line.

Hence, they are collinear and we can say that point $D$ lies between points $A$ and $E .$ The statement is true.

d If we look very closely, we can see that there is not a straight line between

C,

E,

and

F .

The direction changes slightly between

C E

and

E F .

Since the points are not collinear, we cannot say that $E$ is between $C$ and $F .$ Therefore, the statement is false.

Communicate Your Answer p.387

Monitoring Progress p.388-391

Exercises p.392-394

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