Find the equations of two straight lines passing through (1, 2) and making an angle of 600 with the lines x + y = 0. Find also the area of the triangle formed by the three lines.

Given: equation passes through (1,2) and make an angle of 60° with the line x + y = 0


To find: equation of given line and the area of the triangle formed by the three lines


Explanation:


Let A(1, 2) be the vertex of the triangle ABC and x + y = 0 be the equation of BC.


Diagram:



Here, we have to find the equations of sides AB and AC, each of which makes an angle of 60 with the line x + y = 0.


We know the equations of two lines passing through a point x1,y1 and making an angle α with the line whose slope is m.



Here,
x1 = 1, y1 = 2,
α = 60, m = - 1


So, the equations of the required sides are


and





Solving x + y = 0 and
, we get:




AB = BC = AD units


Area of the required triangle square units


Hence, area of the required triangle square units


9