Answer:
x = 48°
Step-by-step explanation:
The triangle on the left has 3 congruent sides and is equilateral with 3 congruent angles, each of 60°
The 3 angles on the base line sum to 180° , that is
60° + 54° + base = 180°
114° + base = 180° ( subtract 114° from both sides )
base = 66°
The triangle on the right has 2 congruent sides and is isosceles with base angles congruent , both 66° , then
x = 180° - (66 + 66)° = 180° - 132° = 48°
