- A120°
- B40°
- C80°
- D100°
Step-by-Step Solution
∠A = 180° − 60° − 40° = 80°, so ∠BAD = 40°. ∠ADC is exterior to △ABD: ∠ADC = ∠BAD + ∠B = 40° + 60° = 100°.
Answer: D) 100°
In △ABC, ∠B = 60° and ∠C = 40°. AD bisects ∠A and meets BC at D. Find ∠ADC.
Class 9Exterior Angle of a TriangleGeometry — Lines and Angles
Master this chapter in 30 minutes a day.
Don't just memorise the answer — build a daily practice habit.
Practice 5 Similar Questions Free →All Exterior Angle of a Triangle practice questions
More Class 9 Exterior Angle of a Triangle practice
The exterior angles at B and C of △ABC add up to 250°. Find ∠A.The angles of a triangle are x, 2x and 3x. Find the exterior angle at the vertex whose…In △ABC, ∠A = x, ∠B = x + 10° and the exterior angle at C (BC produced) is 130°. Find…A roof truss is an isosceles triangle with a ridge (top) angle of 110°. The bottom tie…In the arrowhead figure, ∠A = 50°, ∠ABD = 20° and ∠ACD = 30°. Find ∠BDC (the non-reflex…