Answer Happy

Plz show clear working, thx.
Suppose that a and b are distinct points in C, that m is the midpoint of the line segment with endpoints a and b, and that c is a point on the circle C(m, ž\b – al) with centre m and radius be 316 – al such that c #a and c# b. Use the ratio and the fact that a - c= a - m + m - C and b-c=b- m + m - c to show that Zacb is a right angle. а — с