Answer:
38°
Step-by-step explanation:
EFGH is an isosceles trapezoid (a trapezoid with two congruent legs is isosceles)
∠HGF=70° (base angles of an isosceles trapezoid are congruent)
∠EGH=32° (angles in a triangle add to 180°)
∠FGE=38° (angle subtraction postulate)
P = 10% = 0.1
q = 1 - 0.1 = 0.9
P(at least one defective calculator) = P(1) + P(2) + P(3) + P(4) = 1 - P(0)
The brobability of a binomial distribution is given by

where: n = 4

Therefore,
P(at least one defective calculator) = 1 - 0.6561 = 0.3439