Incorrect. You can set up a right triangle and give the side adjacent to angle A length 2 and the hypotenuse length 5. Then $\displaystyle{{2}}^{{2}}+{{o}}^{{2}}={{5}}^{{2}}\usepackage{cmbright}\Huge\$ . Solve this equation to find the length of the opposite side to angle A, then use the definitions of the trigonometric functions.