Mathematics. Grade 7. Course Book

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TURKISH REPUBLIC OF NORTHERN CYPRUS MINISTRY OF EDUCATION AND CULTURE

GRADE 7

MATHEMATICS COURSE BOOK Authors Prof. Dr. Osman Cankoy Tun� Tagma� Fuat Orta$ MS. Zehra Kavuklu MS. ibrahim Aksaray MS. Nilay Tun�alp MS. Sarem Ozdemir Mehmet Halimoglu MS. Olga Pilli Editing MS. Feridun Ostun Grafical Design Prof. Dr. Osman Cankoy Tune; Tagmac; Zehra Kavuklu Sarem Ozdemir Mehmet Halimoglu Cover Prof. Dr. Osman Cankoy Printing August 2017

RELATION BETWEEN A WORD PROBLEM AND AN EQUATION Analyze the solution of the following problem. The 3more of twice of the amount of Mehmet's money is 15 TL. Find the amount of Mehmet's money. In order to solve such problems we'd better translate the word problem into mathematical language.

2X+3 /

/

2X+3=15

The 3more of twice of the amount of Mehmet's money is 15 TL. Find the amount of Mehmet's money. �X=? Now, we need to find the value of "x" in "2x+3=15". 2x+3=15 2x+3- 3=15 - 3 2x =12 2

2

x =6

Therefore Mehmet has 6 TL.

We turned the following problem into mathematical language. So you find the value of "x". 8more than four times of a number is equal to six times of the number. Find the value of the number. 8more than four times of a number is equal to six times of the number.Find the value of the num'ser. \. \. �= -"---', 4x+8 �4x+8=6x

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7.1.4

• •

Angle Bisectors of a Triangle The following figures show us how an angle bisectors of the triangle ABC is drawn .

•

With the point on A, draw an arc to cut both arms of A at D and E.

A

Considering the points D and E as the center draw two arcs to intersect.

•

A

B The intersection of the arcs can be named as "F". Join A to F and continue to cut the line segment BC. AN bisects the angle DAE.

......___ I N_v_______.l

Now [AN] is the angle bisector of the angle BAC. Angle bisector is usually named as n8 which corresponds to the side BC (a).

K

For the triangle KLM a) Draw the angle bisector of the angle KLM. b) Draw the perpendicular bisector of [KL].

158

C