A
60°
ption (6) is
In the given figure, two of the angles are
indicated. What is the measure of ZB?
(a) 65° (6) 55° (c) 125° (d) 60°
125°
A=60
B=?
C=125
D=?
ANS= clearly,[ACD is the exterior angle of ∆ABC at C.
so, [ACD=[A+[B
i.e., 125°=60°=65°
so, the option (a) is correct, which is the required answer, i. e. answer (a) .
Answers
Answer:
Step-by-step explanation:
In ∆ABC,
∠ACD = ∠A + ∠B (Exterior angle property)
= 70∘ + 40∘
= 110∘
Hence, the measure of ∠ACD is 110∘.
Page No 27:
Question 2:
In ∆PQR, ∠P = 70°, ∠Q = 65 ° then find ∠R.
ANSWER:
In ∆PQR,
∠P + ∠Q + ∠R = 180∘ (Angle sum property)
⇒ 70∘ + 65∘ + ∠R = 180∘
⇒ 135∘ + ∠R = 180∘
⇒ ∠R = 180∘ − 135∘
= 45∘
Hence, the measure of ∠R is 45∘.
Page No 27:
Question 3:
The measures of angles of a triangle are x°, ( x-20)°, (x-40)°. Find the measure of each angle.
ANSWER:
Let us suppose the angles ∠P, ∠Q, ∠Rof a ∆PQR be x°, (x - 20)°, (x - 40)° respectively.
∠P + ∠Q + ∠R = 180∘ (Angle sum property)
⇒ x∘ + (x - 20)° + (x - 40)° = 180∘
⇒ 3x - 60 = 180
⇒ 3x = 240
⇒ x = 80
Therefore,
∠P = 80∘
∠R = (80 - 20)°
= 60∘
∠R = (80 - 40)°
= 40∘
Hence, the measure of each angle is 80∘, 60∘ and 40∘respectively.