1. (a) Construct an angle PQR = 45°. Mark a point S on QR such that QS = 4.5 cm. Construct a circle to touch PQ at Q and also to pass through S.   2. (b) Find the value of k for which the lines kx − 5y + 4 = 0 and 4x − 2y + 5 = 0 are perpendicular to each other. (Leave no spaces in your answer.)   3. (c) If (a, b) ∈ R, name the kind of relation between a and b if a R b => b R a. Does also show a relation of this kind? Explain.