Question

Hey Brainlians..
Help..

Please help me with question no. 31.

Answer 1

Answer:i thinks

Answer is none of this

Option d)

Step-by-step explanation:

Answer 2

Answer:

(a)60 deg

Step-by-step explanation:

wkt, in a quadrilateral sum of angle is 360deg

∠A + ∠B + ∠C + ∠D = 360DEG

140 + ∠B +∠C + 60 = 360

∠B + ∠C = 160...................(i)

EQ(i) * 2

2∠B + 2∠C = 320..............(ii)

GIVEN THAT

∠A + ∠C = 2(∠B+∠D)= 2∠B+2∠D

∠A - 2∠D = 2∠B -∠C

140 - 2(60) = 2∠B - ∠C

2∠B - ∠C= 20.................(iii)

(iii)*2

4∠B - 2∠C = 40................(iv)

(i)+(iv)

2∠B + 2∠C + 4∠B - 2∠C = 320 + 40 = 360deg

6∠B = 360 deg

∠B = (360/60)deg = 60deg