R is a convex polygon. Does R have at least 8 sides?
(1) Exactly 3 of the interior angles of R are greater than 80 degrees.
(2) None of the interior angles of R are less than 60 degrees.
What is convex polygon
A convex polygon is a simple polygon whose interior is a convex set. The following properties of a simple polygon are all equivalent to convexity:
* Every internal angle is at most 180 degrees.
* Every line segment between two vertices of the polygon does not go
exterior to the polygon
To have minimun 8 sides a polygon should have sum of angles 180(n-2)
180(8-2) = 1080
(1). Exactly 3 of the interior angles of R are greater than 80 degrees.
Lets take the greatest value for these angles- 180 and smallest for other 5 -80.
180*3+80*5= 940 < 1080 ..SUFFI
(2) None of the interior angles of R are less than 60 degrees.
Angles can have any value ..NOT SUFFI
Answer A
i hope