Transcript 3.2A –Properties of Triangles

Geometry Notes
T.2.G.2 Investigate the measures of segments to determine the
existence of triangles (triangle inequality theorem)
CGT.5.G.3 Determine, given a set of points, the type of figure based
on its properties (parallelogram, isosceles triangle, trapezoid)

Always name triangles by their vertices
B
A
C

Largest side across from largest angle

Smallest side across from smallest angle

In the following triangle, list the sides in
order from smallest to largest.
C
85o
T
32o
63o
A

In the following triangle, list the angles in
order from largest to smallest
G
5 in
U
6 in
4in
M

The sum of the lengths of any two sides of a
triangle is greater than the length of the third
side.
5 in.
4 in.
3 in.
3+4 >5
3+5 > 4
4+5 > 3
Can a triangle have sides with the given lengths?
Explain.
5inches, 7 inches, 15 inches

No. 5 + 7 ≯ 15
Can a triangle have sides with the given lengths?
Explain.
12 cm, 20 cm, 15 cm

Yes. 12 + 15 > 20
Can a triangle have sides with the given
lengths? Explain.
8 m, 12 m, 4 m

No. 8 + 4 ≯ 12

The lengths of two sides of a triangle are
given. Describe the possible lengths for the
third side.
5 feet, 12 feet
7 < x < 17

The lengths of two sides of a triangle are
given. Describe the possible lengths of the
third side.
18 mm, 24 mm
24 – 18 = 6
6 < x < 42
24 + 18 = 42