Answer:
see explanation
Step-by-step explanation:
The angle at the circumference b , is half the angle subtended at the centre by the arc XZ, that is
b = 0.5 × 72 = 36
OZ and OX are congruent ( both radii of the circle )
Thus Δ OXZ is isosceles with base angles congruent, thus
a = [tex]\frac{180-72}{2}[/tex] = [tex]\frac{108}{2}[/tex] = 54
∠ XZY = 90° ( angle in a semicircle is right )
