Answer:
the answer is 20°
Step-by-step explanation:
each angle in the equilateral triangle is 60°
angle BDC and angle ADB equal 180°
we know that ADB equals 60 so we can subtract 60 from 180 to get 120
add 120 and 40 to get the angle measurements combined (160)
since the inside angles all add up to 180 in a triangle we can subtract 160 from 180 and get 20°
