•WELCOMEWELCOME TO GRADE 7 TO GRADE 7 THE SBI’ S CLASS OF THE SBI’ S CLASS OF SMPN 9 THESMPN 9 THE FUTURE FUTURE LEADER CREATOR LEADER CREATOR

Good morning student !

How are you to day ?

AngleAngleAngleAngle

Our TOPIC TO DAY

Key word 1. Angle is “ sudut “2. Types is “ macam

“3. Supplementary is “

barpelurus “4. Complementary is “

berpenyiku “• Rays is “ sinar

garis “

1.Definition of angle2.Types of angle3.Supplementary angles4.Complementary angles

AngleAngleAngleAngle

understanding of an understanding of an angleangleunderstanding of an understanding of an angleangle

C

A

B

Vertex

Area of angleLeg of angle

The name of angle is ABC or CBA

An angle formed by two rays of which the vertices coincide

Types of anglesTypes of angles

• Angles can be classified according to their size.• An acute angle is greater than 0°, but less than

90 °.• (sudut lancip)• A right angle is an angle that equals exactly 90°.• (sudut siku-siku)• An obtuse angle is greater than 90° but less than

180°• Sudut tumpul)• A straight angle equals exactly 180°• (sudut lurus)• A reflex angle is greater than 180° but less than

360°• A revolution, or a paragon is full 360°

A CUTE ANGLEX ≤ 90°

A RIGHT ANGLEX = EXACTLY 90°

AN OBTUSE ANGLE90° ≤ X ≤ 180°

A STRAIGHT ANGLE0° <X < 180°

A REFLEX ANGLE

HOW TO MEASURING ANGLE ?

SUPLEMENTARY ANGLESSUPLEMENTARY ANGLES(sudut saling berpelurus)(sudut saling berpelurus)

• LOOK AT THE PIGURELOOK AT THE PIGURE

x y

X+Y=180°If , x= 128° SO y= 180°-128°=52°

TWO ANGLES HAVING THE TOTAL SUM OF 180°, ARE CALLED SUPPLEMENTARYANGLES. ONE OF THE ANGLES IS THE SUPLEMENTARY OF THE OTHER ANGLE

EXERCISEEXERCISE

X Y

• X and Y supplementary each others X and Y supplementary each others • a) If xa) If x = 23° so Y= …. = 23° so Y= ….• b) if X= 137° so Y=….b) if X= 137° so Y=….• c) if x= 2y , find how many degree X and Yc) if x= 2y , find how many degree X and Y• d) if x= 2/3 y , how many degree x and yd) if x= 2/3 y , how many degree x and y• e) if x= 2a and y=8a determine I value of a e) if x= 2a and y=8a determine I value of a

, how , how • many degree x and ymany degree x and y

Lagu daerah

solution

COMPLEMENTARY ANGLESCOMPLEMENTARY ANGLES(sudut saling berpenyiku)(sudut saling berpenyiku)

• LOOK THIS RIGHT ANGLELOOK THIS RIGHT ANGLE

XY

X + Y = 90°

If x = 23°, so y = 90°- 23 °

TWO ANGLES HAVING THE TOTAL SUM OF 90° ARE CALLED COMPLEMNTARYONE OF THE ANGLES IS THE COMPLEMENT OF THE OTHER ANGLE

= 67°

exerciseexercise

• X and Y are complementary each othersX and Y are complementary each others• If x= 28°, so Y=….If x= 28°, so Y=….• If x=41° , so Y=….If x=41° , so Y=….• if x = 2y , determine x and yif x = 2y , determine x and y• If x = 1/3y determine x and yIf x = 1/3y determine x and y• If x=4a and y =5a determine value of a , If x=4a and y =5a determine value of a ,

how many degree x and yhow many degree x and y

X

Y

solution

CRTITICAL THINKING1. An angle has a complementary which is five times as big as its supplementary . Count the angle

2 . Attention this figure

10X + 202(15X + 10)Count this angles!

3

P

Q

R S

T

X

IF TXS = (X + 4 )° , SXR =( 3X + 4) AND RXP = ( 2X + 4 ) SOLUTION CLICK HERE

Count this angles!

SOLUTION

1

x

90°- x

5(90°- x)

SO, 5(90° – X ) + X = 180° 450° - 5 X + X = 180°450° – 4X = 180°

450° - 180° = 4X4X =270°

X = 67,5°

2

30 X + 20° +10 X + 20° =180°

40x +20° = 180°

40x =180° - 40°

40x=140°

X=3,5°

2 ( 15X + 10 )° +10 X + 20 ° = 180°

35°+ 20°=55°105° + 20°=125°

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PALEMBANG

1 2

34

5

7

6

8

Properties of an angle of two Properties of an angle of two line parallel intersected by a line parallel intersected by a

transversal linetransversal linel

m

n

ALL THE ANGLES FORM PAIRS OF ANGLES AS FOLLOWING

.

a.Corresponding angles no 1 and 5 ( sudut yg sehadap)b. Alternate interior angles no 3 and 5 ( sudut dalam berseberangan)

. C. .Alternate exterior angles no 1 and 8 (sudut luar berseberangan )

d. Interior angles on the same side of the tranversal no 4 and 5 (sdt dlm sepihake. The exterior angles on the same side of the tranversal 1 and 7 ( sdt luar sepihak)

f. Vertical angles no 1 and 3

1 2

34

5

7

68

l

m

n

ALL THE ANGLES FORM PAIRS OF ANGLES

AS FOLLOWING

a.Corresponding angles no 1 and 5 (sudut yg sehadap)

b.Alternate interior angles no 3 and 5 ( sudut dalam berseberangan)

. C.Alternate exterior angles no 1 and 8 (sudut luar berseberangan )

d. Interior angles on the same side of the tranversal no 4 and 5 (sdt dlm sepihak)

e. The exterior angles on the same side of the tranversal 1 and 7 ( sdt luar sepihak)

f). Vertically opposite angles no 1 and 3

EXERCISEEXERCISEA

B

8

5

4 3

21

67

L

n

m

m and n are two parallel line and l crosses at A and B . What are the relation of fair angles below

a) A1 and B5

b) A1 and B8

c) A4 and B5

d) A4 and B6

Corresponding anglesThe exterior angles on the same side of the tranversalThe inteterior angles on the same side of the tranversal Alternate interior angles e) A4 and

A2Vertically opposite angles

A

B

8

5

4 3

21

67

L

n

m

m and n are two parallel line and l crosses both line at A and B . If A1 45°

How many degree a) A3

b) A2

c) B6

d) B8

A

B

C D

E

Look at the figure. Line BE and CD are

parallel line

What are the relation of fair angles bellow

a). B1 and C1

b) E1 and E3

c) D2 and E4

d) C2 and D2

e) B1 and E1

1

1

1

1

4

2

2

2

2

33 4

DIVIDING LINEDIVIDING LINEDIVIDING LINE IN TO FOUR PARTSDIVIDING LINE IN TO FOUR PARTSDIVIDING LINE IN TO TWO PARTSDIVIDING LINE IN TO TWO PARTS