+ All Categories
Home > Documents > Geometry Unit 5: Triangle Parts. CONCURRENT: Concurrent: When three or more lines intersect at the...

Geometry Unit 5: Triangle Parts. CONCURRENT: Concurrent: When three or more lines intersect at the...

Date post: 30-Dec-2015
Category:
Upload: clementine-bryan
View: 213 times
Download: 0 times
Share this document with a friend
Popular Tags:
65
Geometry Unit 5: Triangle Parts
Transcript

GeometryUnit 5: Triangle Parts

CONCURRENT:

Concurrent:

When three or more lines intersect at the same point, P

P

MIDSEGMENT:

Triangle Midsegment:

Segment connecting the midpoints of two sides of a triangle

Triangle Midsegments

• Parallel to the third side of the triangle

Triangle Midsegments

• Parallel to the third side of the triangle

• Half the length of the third side of the triangle

BISECTORS

Bisectors

Both types of bisectors (Angle Bisectors and Perpendicular Bisectors) will lead to circles.

Bisectors

Both types of bisectors (Angle Bisectors and Perpendicular Bisectors) will lead to circles.

• The circles will be inscribed in or circumscribed about triangles.

PERPENDICULAR BISECTORS

Perpendicular Bisectors

• Lines that bisect a side and are perpendicular to it

PERPENDICULAR BISECTOR

Bisects a side and makes a 90 angle with it

Perpendicular Bisectors (in purple)

• Concurrent at the CIRCUMCENTER of each green triangle

Perpendicular Bisectors

• Circumcenter can be inside, on, or outside of the triangle

Perpendicular Bisectors

• Circle 1: circumcenter is outside triangle• Circle 2: circumcenter is inside triangle

. .circumcenter

circumcenter

Perpendicular Bisectors

• purple radii of circle go from circumcenter to each vertex of the triangle

r

r

Perpendicular Bisectors

• Can you identify three isosceles triangles in each figure?

r

r

Perpendicular Bisectors

• Lines that bisect a side and are perpendicular to it

• Concurrent at the Circumcenter of the triangle

• Circumcenter can be inside, on, or outside of the triangle

• Radii of circle go from circumcenter to each vertex of the triangle

Angle Bisector

Angle Bisector

Bisects the angle

Angle BisectorConcurrent at the INCENTER

(center of circle INSCRIBED in triangle)

Angle BisectorConcurrent at the INCENTER

(center of circle INSCRIBED in triangle)

MEDIAN

MEDIANSegment from vertex to opposite

side’s midpoint

(Nothing to do with the angle!!)

MEDIAN

Concurrent at CENTROID

(center of gravity)

MEDIAN

The center of gravity is the BALANCE POINT.

MEDIAN

The CENTROID must be inside of the triangle!

ALTITUDE

ALTITUDE

Perpendicular segment from a vertex to the side opposite (or extension of the side

opposite).

ALTITUDE

Height of the triangle

(perpendicular to the base)

ALTITUDES

ALTITUDES

Concurrent at the ORTHOCENTER

orthocenter.

ALTITUDES

Can be outside of a triangle.

altitude

Quick Review

MEDIAN

MEDIAN

Concurrent at CENTROID

(center of gravity)

. Centroid

Angle Bisector

Angle BisectorConcurrent at the INCENTER

(center of circle INSCRIBED in triangle)

Angle BisectorConcurrent at the INCENTER

(center of circle INSCRIBED in triangle)

. Incenter

ALTITUDE

ALTITUDES

Concurrent at the ORTHOCENTER

orthocenter.

PERPENDICULAR BISECTORS

Perpendicular Bisectors:

Concurrent at the Circumcenter

. circumcenter

Perpendicular Bisectors

• Radii of circle go from circumcenter to each vertex of the triangle

r

r

r

BISECTORS

Bisectors

Both types of bisectors (Angle Bisectors and Perpendicular Bisectors) will lead to circles.

Problem: Three cities want to build a park that is the same distance from each of their city centers. What should they do?

Kenmore

Shoreline

MLT

Which “triangle center” will be the same distance from each city center?

Shoreline

Kenmore

Shoreline

MLT

The CIRCUMCENTER

Shoreline

Kenmore

Shoreline

MLT

Which triangle segments or lines are used to find the circumcenter?

Shoreline

Kenmore

Shoreline

MLT

PERPENDICULAR BISECTORS

Shoreline

Kenmore

Shoreline

MLT

PERPENDICULAR BISECTORS(green lines) are concurrent at the

CIRCUMCENTER.

Kenmore

MLT

CircumcenterShoreline

The Circumcenter is equidistant from each city center.

Kenmore

MLT

Circumcenter

Shoreline

The distance is the RADIUS of the circle centered at the CIRCUMCENTER.

Kenmore

MLT

C

Shoreline

r

r r

Problem: Three cities want to build a toxic waste dump that is the same distance from each of their city centers. What should they do?

MLTKenmore

Shoreline

Which “triangle center” will be the same distance from each city center?

MLTKenmore

Shoreline

Which “triangle center” will be the same distance from each city center? The CIRCUMCENTER

MLTKenmore

Shoreline

Which triangle segments or lines are used to find the circumcenter?

MLTKenmore

Shoreline

Which triangle segments or lines are used to find the circumcenter?

PERPENDICULAR BISECTORS

MLTKenmore

Shoreline

PERPENDICULAR BISECTORSare concurrent at the CIRCUMCENTER.

Kenmore

Shoreline

MLT

Circumcenter

The Circumcenter is equidistant from each city center.

KenmoreShoreline

MLT

Circumcenter

The distance is the RADIUS of the circle centered at the CIRCUMCENTER.

KenmoreShoreline

MLT

Circumcenter

radius

The circumcenter can be outside of the triangle.

KenmoreShoreline

MLT

Circumcenter

radius

The centroid and incenter must be inside

of the triangle.


Recommended