Question

x,(x 20),(x 40),(x 60),(x+80) find the smallest angle of pentagon

Answer 1

Now We know that interior angles of a pentagon are 
(n-2)180 where n is the number of sides
=540 degree
Hence
Sum of x,x+20,x+40,x+60,x+80=540
So
x+x+20+x+40+x+60+x+80=540
5x+200=540
5x=340
x=68 degree
Hence the smallest angle of the pentagon is 68 degree

Answer 2

Given : Pentagon
The angles are given : x , (x+20) ,  (x + 40) , (x + 60) , (x + 80)
we know that the sum of angles of a pentagon = 540°
∴x+x+20+x+40+x+60+x+80 = 540°
⇒5x + 200 = 540
⇒5x = 540 - 200
⇒5x = 340
⇒x = 340/5
∴x = 68
∴the smallest angle (x) = 68°