Which is the range of possible side lengths of the missing side?

5 < x <21

Step-by-step explanation:

The side lengths of a triangle :

The sum of two side lengths selected at random must be bigger than the third side length and their difference must be smaller than the third side length

If we call the third side x than

x must be smaller than 13 + 8 and x must be bigger than 13 - 8 which means

5 < x <21

3x + 18 = 147°

step-by-step explanation:

3x + 18 = 147°, because the value of the central angle is equal to the value of the arc formed by it.

i hope i you.