The angle between the lines $$2x - y + 3 = 0$$ and $$x + 2y + 3 = 0$$ is
Correct option is A. $$90^\circ$$
$$\textbf{Step 1: Find the slope of lines by taking ratio of coefficients of x and y with a minus sign.}$$
$$\text{We know that, slope = }\dfrac{\text{-coefficient of x}}{\text{coefficient of y}}$$
$$\begin{gathered}\ \ \ \ \ \ \ \ \ \ \ \ \ 2x-y+3=0 \quad\Rightarrow\quad m_{1}=-\dfrac{2}{-1}=2 \\x +2y+3=0 \quad \Rightarrow m_2=-\dfrac{1}{2} \end{gathered}$$
$$\textbf{Step 2: Check lines are perpendicular or not by computing }\boldsymbol{m_1m_2.}$$
$$m_1m_2=2\times \dfrac{-1}{2}=-1$$
$$\therefore \text{Both lines are perpendicular.}$$
$$\text{Angle between lines is }90^\circ$$
$$\textbf{Hence, Option A is correct.}$$