Isosceles and Equilateral Triangles

Isosceles and Equilateral Triangles

Isosceles Triangle

• If a triangle has two congruent sides, then it will have two congruent angles.

• If a triangle has two congruent angles, then it will have two congruent sides.

Open Ended

If the legs are congruent then the base angles are ________________.

Open Ended

If AB = 5cm, then BC = ?

If m<A = 50 degrees, then m<C = ? 

Multiple Choice

What is the m<A?

• 46

• 90

• 88

• 134

Multiple Choice

What is the name of this kind of triangle?

• Right

• Scalene

• Isosceles

• Equilateral

Multiple Choice

If two sides of a triangle are congruent, then the _________________ opposite those sides are congruent.

• sides
• vertices
• angles
• measures

Multiple Choice

If an isosceles triangle has a base angle measuring 40°, then what measure is the vertex angle?

• 120°
• 100°
• 40°
• 80°

Multiple Choice

Find the value of x

• 41

• 45

• 31

• 98

Multiple Choice

Find x

• 10

• 32

• 116

• 16

Multiple Choice

Which of the following terms best describes Angle d? 

• Remote interior angle
• Corresponding angle
• Exterior angle
• Interior angle

Equilateral Triangle

• If a triangle has 3 congruent sides, then it will have 3 congruent angles.

• If a triangle has 3 congruent angles, then it will have 3 congruent sides.

Open Ended

Each angle in an equilateral triangle measures _______.

Multiple Choice

What is the measure of BC?

• 12

• 6

• 10

• Not enough information

Multiple Choice

What is the value of x?

• 16

• 60

• 8

• Not enough information

Multiple Choice

What is the name of this kind of triangle?

• Right

• Isosceles

• Scalene

• Equilateral

Multiple Choice

The sides of an equilateral triangle have...

• different measures.
• Febtober.
• equal measures.
• 60°.

Multiple Choice

What do the angles in an equilateral triangle measure?

• 30, 60, 90

• 60, 60, 60

• 45, 45, 90

• 35, 55, 90

Multiple Choice

• 9

• 10

• 6

• 11

Multiple Choice

What is the value of x?

• 51

• 49

• 78

Multiple Choice

• A

• B

• C

• D

Multiple Choice

• 12

• 11

• 8

• 6