Answer: Option A
:
 Each part: 2 Marks
(a)  Steps of construction:
Draw $\stackrel{Â}{PQ}=3.5\text{Â}cm$
With P as the centre, draw an arc with the radius equal to 4.5 cm.
With Q as the centre, draw another arc with radius 5.5 cm to cut the previous arc at R.
Join R to P and Q.
PQR is the required triangle.

Thus, we see that if three sides of a triangle are given and the sum of any two sides is always more than the third side, then a triangle can be constructed. This is known as SSS criterion for construction of triangles.
(b)   Steps of construction:
Step 1: Draw a line segment QR = 6 cm.
Step 2: Construct an angle of 60${}^{∘}$ at point Q.
Step 3: Draw an arc on the ray QX with Q as the centre and the radius equal to 4 cm.
Step 4: Name the point where the arc cuts the ray QX, as P.
Step 5: Join points P and R.
PQR is the required triangle.