http://www.ck12.org Chapter 5. Relationships with Triangles
Example C
List the sides in order, from least to greatest.
Let’s start with 4 DCE. The missing angle is 55◦. Therefore the sides, in order areCE,CD, andDE. For 4 BCD,
the missing angle is 43◦. The order of the sides isBD,CD, andBC. By the SAS Inequality Theorem, we know that
BC>DE, so the order of all the sides would be:BD=CE,CD,DE,BC.
Watch this video for help with the Examples above.
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/52537CK-12 Foundation: Chapter5ComparingAnglesandSidesB
Concept Problem Revisited
Even though the two sets of lengths are not equal, they both add up to 23. Therefore, the second rider is further away
from the parking lot because 110◦> 90 ◦.
Vocabulary
TheTriangle Sum Theoremstates that the three angles in a triangle always add up to 180◦. Themedianin a
triangle connects the midpoint of one side to the opposite vertex. Anisosceles triangleis a triangle with at least two
congruent sides.
Guided Practice
- IfX Mis a median of 4 XY ZandXY>X Z, what can we say aboutm^6 1 andm^6 2?