DefinitionDefinition

Triangel is a equilateral which Triangel is a equilateral which have three straigh sides and have three straigh sides and

three anglesthree angles

Types Of TriangelTypes Of Triangel

Based on the length of the sidesBased on the length of the sides Equilateral triangleEquilateral triangle is a triangel having is a triangel having

three congruent sidesthree congruent sides Isosceles triangelIsosceles triangel is a triangel having is a triangel having

two congruent sidestwo congruent sides Scalen triangleScalen triangle is a triangel having no is a triangel having no

congruent sidescongruent sides

Based on measure of the angleBased on measure of the angle

Right triangleRight triangle is a triangle that has is a triangle that has one 90one 90° ° angleangle

Obtuse angleObtuse angle is triangle that has one is triangle that has one obtuse angel, >90obtuse angel, >90°°

Acute triangelAcute triangel is a triangel that has is a triangel that has three acute angel, <90three acute angel, <90°°

Based on the angel two sidesBased on the angel two sides

Right isosceles triangle is a triangle Right isosceles triangle is a triangle that has one 90° angle and two equal that has one 90° angle and two equal sidessidesObtuse isosceles triangle is a triangle Obtuse isosceles triangle is a triangle that has one obtuse angle >90° and that has one obtuse angle >90° and two equal sidestwo equal sidesAcute isosceles triangle is a triangle Acute isosceles triangle is a triangle that has one acute angle <90° and that has one acute angle <90° and two equal sidestwo equal sides

The Sum Of A TriangleThe Sum Of A Triangle

The sum of all angle in a triangle is 180°The sum of all angle in a triangle is 180°

Example:Example:

X= 180°°-(55°°+65°°)X= 60°°

OrOr

X+55°+65°=180°X+55°+65°=180° X+120= 180° X+120= 180° x=60°x=60°

The sum of two sudes in each triangle always more long from third side, if a, b, c, is triangle’s sides, so the all of them must

fullfill

a + b > ca +c + > bb +c > a

Special Line Of TriangelSpecial Line Of Triangel

High line is line which interested from a High line is line which interested from a vertex and upright with side in front of itvertex and upright with side in front of it

Devided line is line which devide a Devided line is line which devide a triangel’s vertex to two vertex same sidestriangel’s vertex to two vertex same sides

weight line is lin which interested from a weight line is lin which interested from a vertex to central point side in front of itvertex to central point side in front of it

exist line is line which interestedfrom a exist line is line which interestedfrom a central point side and upright with that central point side and upright with that sideside

Perimeter and area of Perimeter and area of triangletriangle

P=a+b+cP=a+b+c

If P is perimeter of a triangle having the side If P is perimeter of a triangle having the side a,b and c, then the perimeter of triangle can a,b and c, then the perimeter of triangle can be stated as P=a+b+cbe stated as P=a+b+c

ba

c

The exterior and interior angels The exterior and interior angels of a triangleof a triangle

• An exterior angels of a triangle is an An exterior angels of a triangle is an angles formed by the side of the of a angles formed by the side of the of a triangle with the extension of the triangle with the extension of the other side of triangle.other side of triangle.

• An interior angle of a triangle is an An interior angle of a triangle is an angle formed by the side of a triangle angle formed by the side of a triangle with the intension of the other side of with the intension of the other side of the trianglethe triangle

U

TSR

<T,<U, and <TSU are the interior angle of <T,<U, and <TSU are the interior angle of

<RSU is the exterior angle of<RSU is the exterior angle of

The measure of an exterior angle of a triangle The measure of an exterior angle of a triangle is equal to the sum of two interior angles is equal to the sum of two interior angles which aren’t supplementary to the exterior which aren’t supplementary to the exterior angle.angle.

STU

TSU

MEMBERS:MEMBERS:

-Indra-Indra Aulia Rahman (9)Aulia Rahman (9)

-Nurita A. Tyas (14)-Nurita A. Tyas (14)

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-Realita Mustika Dewi (18)-Realita Mustika Dewi (18)

-Siswanto Adi Wijanarko (22)-Siswanto Adi Wijanarko (22)