Loading [MathJax]/jax/output/SVG/jax.js
 
  Questions   
Sort: 
 #1
avatar+26396 
+2

The interior angles of a convex polygon are in an arithmetic progression.
If the smallest angle is 100 degrees and common difference is  10 degrees ,
then find the number of sides.

 

Let the sides of the polygon n 


Arithmetic progression:sum=100+110+120+130++(100+(n1)10)sum=(100+(100+(n1)10)2)nsum=(100+100+10n102)nsum=(190+10n2)nsum=(95+5n)n

 

Interior angles of a convex polygon: sum=(n2)180

 

(95+5n)n=(n2)18095n+5n2=180n21805n285n+360=0|:5n217n+72=0n=17±1724722n=17±2892882n=17±12n=9orn=8

 

laugh

Jun 27, 2021
Jun 26, 2021

2 Online Users