Flag Algebra> the interior angles fo a polygon are inar...
question mark

the interior angles fo a polygon are inarithmatic progration.The smallest angle is 120 degree and the common difference is 5 degree.Find the number of sides?

Amit sharma , 7 Years ago
Grade 11
anser 1 Answers
Pratyush Ranjan Roul

Last Activity: 7 Years ago

the sequence seems to be 120, 125, 130 …..........
So,
Sn=n/2{ 240 + (n-1)5 }-----------------(i)
but the angles can never be 180o as it does not form a vertex and hence no side
So, it extend upto 175o
Sn also equals to  n/2{a + an}
Sn=n/2{120 + 175}--------- (ii)
Equating i and ii,
295 = 240 + 5n – 5
=> 5n = 60
=> n = 12
 

Provide a better Answer & Earn Cool Goodies

Enter text here...
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments


Ask a Doubt

Get your questions answered by the expert for free

Enter text here...