9514 1404 393
Answer:
48°
Step-by-step explanation:
ΔACB is isosceles, so angles A and B have the same measure. The measure of angle C in that triangle is ...
∠C = 180° -2(69°) = 42°
Angle C in ΔCDE has the same measure. Angle D is the complement of that:
∠D = 90° -42° = 48°
_____
The relations we used are ...
- the sum of angles in a triangle is 180°
- base angles of an isosceles triangle are congruent
- vertical angles are congruent
- acute angles in a right triangle are complementary
