Question

Pls show solving and step by step explanation

Answer 1

So, We have to know the 2 angles of quadrilateral given here other than x.

$\rm\green{\angle BFE~=~60°}$

$\rm{\angle ABF~=~70°}$

$\rm{\angle ABF~+~\angle FBC~=~180°(Linear~pair)}$

$\rm{\angle FBC~+~70°~=~180°}$

$\rm\green{\angle FBC~=~110°}$

$\rm{\angle CEF~+~\angle DEC~=~180°~(Linear~pair~)}$

$\rm{\angle CEF~+~60~=~180}$

$\rm\green{\angle CEF~=~120°}$

We know that sum of all angles of quadrilateral is 360°

So,

$\rm{60°~+~120°~+~110°~+~x~=~360°}$

$\rm{290~+~x~=~360}$

$\rm{x~=~360~-~290}$

$\rm\pink{x~=~70°}$

$\fbox\blue{.°.~Value~of~x~=~70°}$

_______________________

$\red{\sf\frak{-~shashi1979bala}}$

Answer 2

Answer:

option b.

Step-by-step explanation:

ABC and FED are straight lines

The angle of the straight line is 180°

so,∆ABF+∆CBF=180°

70°+∆CBF=180°

∆CBF=180°-70°

Therefore, ∆CBF=110°

Similarly ,∆CEF+∆DEC=180°

∆CEF+60°=180°

∆CEF=180°-60°

Therefore, ∆CEF=120°

TRIANGLE BCEF = 360°

∆CBF+∆BFE+∆CEF+∆ECB=360°

110°+60°+120°+ x=360°

x=360°-110°-60°-120°

x=360°-290°

Therefore, x=70°