Question

Question 13
A polygon has prime number of sides. Its number of sides is equal to the sum of the two least consecutive primes. The number of diagonals of the polygon is
a) 4
b) 5
c) 7
d) 10

Answer 1

The two least consecutive primes numbers are 2 and 3.

$\therefore$ 2 + 3 = 5

So,the total number of sides of polygon (n) = 5

$\therefore$ Number of diagonals = $\frac{n(n-3)}{2}$

= $\frac{5(5-3)}{2}$

= $\frac{10}{2}$

= $5$