Calculate the size of angle BCD.

From the image, we can see:

• Angle A is a right angle: $\angle A = 90^\circ$.
• Angle B is given: $\angle B = 128^\circ$.
• Angle D ($\angle ADC$) can be read from the protractor. The line DA aligns with $0^\circ$ and the line DC aligns with $50^\circ$ on the outer scale. So, $\angle D = 50^\circ$.

$$(90^\circ + 128^\circ + 50^\circ) + \angle BCD = 360^\circ$$ $$268^\circ + \angle BCD = 360^\circ$$

$$\angle BCD = 360^\circ - 268^\circ$$ $$\angle BCD = 92^\circ$$

The size of angle BCD is $\text{92}^\circ$.