please help me to solvethis
Answers
Answer:
The answer is 34 according to the bisector property of triangles on the same base see ex.5.4 ncert maths book last question class 9
Step-by-step explanation:Given: ABC is a triangle,
In which
Also, BE and CE are the angle bisector of the angles ABC and ACD,
We have to prove that: ∠BEC = 1/2 ∠BAC
Proof:
BE is the angle bisector of angle ABC,
⇒ ∠ABE = ∠EBC
And, CE is the angle bisector of angle ACD,
⇒ ∠ACE = ∠ECD
By the exterior angle theorem,
∠ACD = ∠ABC + ∠BAC
⇒ (∠ACE + ∠ECD) = (∠ABE + ∠EBC) + ∠BAC
⇒ 2∠ECD = 2∠EBC + ∠BAC
⇒ ∠BAC = 2(∠ECD - ∠EBC) ---------(1)
Now, again by exterior angle theorem,
∠ECD = ∠EBC+∠BEC
⇒ ∠BEC = ∠ECD - ∠EBC ------------(2)
By equation (1) and (2),
∠BAC = 2 ∠BEC
⇒ 1/2 ∠BAC = ∠BEC
Hence, proved.
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Answer:
34°
Step-by-step explanation:
let, angle ABC = 2x and angle ACD = 2y
since, BE was bisector, angle ABE = angle EBC = 2x/2 = x
since, CE was bisector, angle ACE = angle ECD = 2y/2 = y
angle ABC + angle BAC = angle ACD (exterior angle property)
⇒ 2x + 68 = 2y ⇒ x - y = -34
angle BCE + angle ECD = 180 (linear pair)
⇒ angle BCE = 180 - y
in triangle BCE
angle EBC + angle BCE + angle BEC = 180 (angle sum property)
⇒ x + 180 - y + angle BEC = 180
⇒ x - y = - (angle BEC)
⇒ - 34 = - (angle BEC)
⇒ angle BEC = 34°