Base Angles Theorem

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

• 120°

• 100°

• 40°

• 80°

Find x

• 10

• 32

• 116

• 16

Solve for the value of X.

X=_____

Find the value of x

• 6

• 12

• 2

• 72

What is the value of x?

• 51

• 49

• 78

• 50

Find the value of x.

• 1

• 4

• 5

• 8

Find the value of x .

• x = 4

• x = 5

• x = 6

• x = 20

The Base Angle Theorem states that " in an isosceles Δ, the angles that sit ___________ the congruent sides are congruent to each other ".

• adjacent to

• opposite

In isosceles ΔDEF, which angles are the base angles?

• Angles D and E

• Angles E and F

• Angles D and F

• None of these

• Angles D and E
• Angles E and F
• Angles D and F
• None of these