1. For problem 17: The slope of the wedge is given as $x$, and we need to find $\tan x$. Since slope is defined as the ratio of the vertical change to the horizontal change, $\tan x$ is the slope itself. 2. Therefore, $\tan x = 2/3$, matching option C. 3. For problem 18: Angles whose sum is 180° are known as supplementary angles. 4. Therefore, the correct answer is C: supplementary angles. 5. For problem 19: Given that $\triangle DEC$ is equilateral and ABCD is a square, consider the following: - Each angle in an equilateral triangle is 60°. - ABCD is a square, so each angle is 90°. 6. Since $\triangle DEC$ is equilateral, $\angle DEC = 60^\circ$. 7. Point E lies above side DC, which is horizontal. So, $\angle DEA$ can be found by subtracting the angle between DE and EA from 90°. 8. The result is $\angle DEA = 30^\circ$, matching option C. Final answers: - 17: $\tan x = \frac{2}{3}$ - 18: Supplementary angles - 19: $\angle DEA = 30^\circ$