Can someone help plz?!

10 cm

Step-by-step explanation:

The diameter is a chord (line) that connects on both ends of a circle which includes the center point of the circle. The radius comes from the center point of the circle to one end of the circle.

Diameter is therefore 2 radii (radius).

So if diameter is given and you want to find the radius, divide it by two to find the answer.

20 ÷ 2 = 10 cm

c: lkllmn.

hope it's you

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!