Could someone me need answer asap

Here we use altitude rule which states that

Ratio of part of hypotenuse and height= ratio of height and remaining part of hypotenuse .

So here parts of hypotenuses are r and s and h is the hypotenuse. SO we will get

Correct option is s.

You can start by finding the radius and diameter of each circle: Circle A has a radius of 5 units and a diameter of 10 units, while circle C has a radius of 2 units and a diameter of 4.  Then you can divide the two radii (5/2) and the two diameters (10/4).  Since both give you an answer of 2.5, that is proof that the two circles are similar.  

Hope this helps!