Atriangle has points r(-2,0) ,s(2,8) and t (8,2) as shown in the group. m is the midpoint of rt . what is the length of sm

The midpoint is calculated by averaging the coordinates of its endpoints:

Now we can use the usual distance formula to get the length of SM:

this may not be at all, but i use the same website you're using for school, and if i'm stuck doing one of these i try to look for it on the section.

ca = ec

cpctc makes it so that corresponding parts of the triangle you proved to be equal are equal, the other options aren't part of the part of the triangles you proved to be equal.