Question

If the sum of all interior angles of a convex polygon is ${1440}^{\circ }$, then the number of sides of the polygon is?

• A. $8$
• B. $10$
• C. $11$
• D. $12$

Answer 1

Answer: (B)

$10$

If n is the number of sides of the polygon, then
$(2n-4)\times {90}^{\circ }={1440}^{\circ }$
or $2n=20$
or $n=10$