Question

Find the number of diagonals of the following polygons whose number of sides are given below:
(i) 8
(i) 12
(iii) 24
(iv) 30
Find the sum of interior angles of polygons​

Answer 1

Answer:

(i)20

(ii)54

(iii)252

(iv)405

Step-by-step explanation:

Use this formula

Number of Diagonals = n(n-3)/2

where, n = no. of sides of polygon

Answer 2

Answer:

1. 20

2. 54

3. 252

4. 405

Step-by-step explanation:

Number of Diagonals = n(n-3)/2

where n is the number of sides

1. 8 x 5 / 2 = 20

2. 12 x 9/ 2 = 54

3. 24 x 21 / 2 = 252

4. 30 x 27 /  2 = 405

Sum of interior angles ( n − 2 ) × 180  where n  is the number of sides.