Download getting to know triangles

GETTING TO KNOW
TRIANGLES
7TH GRADE MATH
BY MRS. BRUSH
 Triangles are everywhere.
 They can be found bracing a bridge.
 Triangles can be found racking up billiard
balls.
Triangles can be seen holding up
shelves.
 A triangle is a
polygon with 3
sides.
 Triangles can be
classified by sides.
 Triangles can be
classified by
angles.
TRIANGLES BY SIDES
 SCALENE
 ISOSCELES
 EQUILATERAL
SCALENE TRIANGLE
 WHEN 3 PEOPLE
GET ON THE
SCALES TO SEE
HOW MUCH THEY
WEIGHT, EACH ONE
WEIGHS A
DIFFERENT
AMOUNT.
SO…………
 A scalene triangle has
no equal sides.
All sides are different
lengths.
Isosceles Triangles
 Isosceles triangles
have 2 equal sides.
 The angles opposite
the equal sides are
also equal. <B =
<C AB = AC
Equilateral Triangles
 All 3 sides of an
equilateral triangle are
equal.
 Each angle of an
equilateral triangle are
equal.
 Each angle must be 60
degrees.
 Now let’s review.
 What kind of triangle has all 3 sides and
angles equal?
Equilateral Triangle
 What kind of triangle has all sides a different
length ?
SCALENE TRIANGLE
 What kind of triangle has 2 equal sides?
AN ISOSCELES TRIANGLE
TRIANGLES BY ANGLES
Acute
Right
Obtuse
Acute triangles
All angles are less than 90 degrees.
 A right triangle has one 90 degree angle.
OBTUSE TRIANGLE
 An obtuse triangle has one obtuse angle.
The obtuse angle is more than 90 but less
than 180 degrees.
DISCUSSION QUESTIONS
 Is it possible to have a right equilateral
triangle?
 Could you have a triangle that is isosceles
and acute?
CREDITS
 Microsoft clip art.
 wwwmath.com/school/subject/practice
 www.harcourtschool.com/glossary/math2