Question

Refer to the given figure and find the value of x​

Answer 1

Step-by-step explanation:

angleB=120+b(linear pair)

180-120=b

60=b

Angle(A+B+C+D)=360

x+60+2x-40+70=360

3x+90=360

3x=360-90

3x=270

x=270/3

x=90

Answer 2

Given :

∠ ADC = 70°

∠ DCB = ( 2x -40)°

∠ DAB =x

To find:

∠x =?

Solution:

ABCD is a quadrilateral.

Sum of four angles of a quadrilateral is 360°.

∠ADC = 70°

∠ABC = 180-120

= 60°

(linear pair angles)

Linear pair angles are those angles which are formed when two lines intersect each other at a single point and the angles are adjacent to each other after the intersection of the two lines.

The sum of angles of a linear pair is always equal to 180°.

In quadrilateral ABCD

∠ADC + ∠ABC + ∠DAC + ∠DBC =360

( Sum of angles of a quadrilateral is 360°)

70 + 60 + (2x -40) + x = 360°

130 + 2x + x - 40 = 360°

130 - 40 + 3x = 360

90 + 3x = 360

3x = 360 - 90

3x = 270

x = 270/3

x = 90°

∠DAB = 90°

Hence value of x = 90°