Question

plz answer this fast​

Answer 1

Concept to be used:

A polygon with x sides exactly forms (x-2) triangles inside.

The sum of interior angles of 22 triangles is

$\sf{180\times22=3960}$°

None of the above has the solution.

For your information,

Let us consider a square.

Why exactly 2 triangles? Because we can't draw diagonals to the adjacent sides, there will be (x-3) lines, and each line forms a triangle.

No, it is not enough because we missed one triangle. Since it 'divides' the polygon, it will give us (x-3)+1 triangles.

Therefore there form exactly (x-2) triangles.

Why is $180\times22$ a correct method?

Since the angles are part of those polygons, it is correct to multiply the triangle interior angle sum 180°.