a diagonal of a polygon is a straight line joining any 2 non-adjacent corners.a decagon has 10 corners. .how many diagonals does it have ?

Joining any two points will produce a line

there are C(10,2) such lines or 45 of them
But, 10 of them will be the actual sides of the polygon, the others are diagonals

number of diagonals = 45-10 = 35

thanks for your kindness

To find the number of diagonals in a decagon (a polygon with 10 corners), you can use the formula:

Number of diagonals = (n * (n - 3)) / 2

where "n" represents the number of corners of the polygon.

In this case, n = 10, so let's substitute it into the formula:

Number of diagonals = (10 * (10 - 3)) / 2

Number of diagonals = (10 * 7) / 2

Number of diagonals = 70 / 2

Number of diagonals = 35

Therefore, a decagon has 35 diagonals.

To find the number of diagonals in a decagon, we can use a simple formula.

The formula for the number of diagonals in a polygon is given by:
Number of diagonals = (n * (n - 3)) / 2

where 'n' is the number of sides of the polygon.

For a decagon, n = 10, so we substitute this value into the formula:
Number of diagonals = (10 * (10 - 3)) / 2
= (10 * 7) / 2
= 70 / 2
= 35

Therefore, a decagon has 35 diagonals.