complete question:
AD = BD = CD. If angle BAD = 50°, what is angle ABC?
(Note: figure not drawn to scale.)
Answer:
(D) 90°
Step-by-step explanation:
The figure below is the triangle for the complete question. The side AD = BD = CD. The triangle ABD is an isosceles triangle . AD and BD are equal. Since the angle BAD = 50° , angle ABD = 50°.
Sum of angle in a triangle = 180°
triangle ADB = 180 - 50 + 50 = 80°
Angle BDC = 180 - 80 = 100°. (angle on a straight line)
Since BD and CD are equal(Isosceles triangle) the angle DBC and DCB are equal. The angle DBC and DCB = 80/2 = 40°.
angle ABC = angle ABD + angle DBC
angle ABC = 50° + 40°
angle ABC = 90°
