Question

Classify the following pair of angles as complementary and supplementary. [4 MARKS]

(i) ${120}^{\circ },{50}^{\circ }$

(ii) ${60}^{\circ },{120}^{\circ }$

(iii) ${39}^{\circ },{61}^{\circ }$

(iv) ${65}^{\circ },{25}^{\circ }$

Answer 1

Each part: 1 Mark

Two angles are complementary when they add up to ${90}^{\circ }$

Two angles are supplementary when they add up to ${180}^{\circ }$

(i) ${120}^{\circ }+{50}^{\circ }={170}^{\circ }$

Angles are neither complementary nor supplementary.

(ii) ${60}^{\circ }+{120}^{\circ }={180}^{\circ }$

Angles are supplementary.

(iii) ${39}^{\circ }+{61}^{\circ }={100}^{\circ }$

Angles are neither complementary nor supplementary.

(iv) ${65}^{\circ }+{25}^{\circ }={90}^{\circ }$

Angles are complementary.