Question

Complementary angle of $72{\frac{1}{2}}^{\circ }$ is:

• A. ${17}^{\circ }$
• B. $18{\frac{1}{2}}^{\circ }$
• C. $21{\frac{1}{2}}^{\circ }$
• D. $17{\frac{1}{2}}^{\circ }$

Answer 1

The correct option is D $17{\frac{1}{2}}^{\circ }$

We know, two angles are complementary when they add up to ${90}^o.$

Given, measure of one complementary angle is $72{\frac{1}{2}}^o={\frac{145}{2}}^o.$

$\Rightarrow$ Measure of other complementary angle $={90}^o-{\frac{145}{2}}^o$ $={\frac{35}{2}}^o=17{\frac{1}{2}}^o.$

$\therefore$ Measure of a complementary angle of $72{\frac{1}{2}}^o=$ $17{\frac{1}{2}}^o.$

Therefore, option $D$ is correct.