The points A(-1, -2), B(7, 2) and C(k, 4), where k is a constant are the vertices of traingle ABC. Angle ABC is a right angle.
1. Calculate the value of k
2. Find the exact area of traiangle ABC
3. Find the equqtion for the stright line l passing therough B and C. Give your answer in the form of ax + by = c = 0 , where a, b and c are integers.
The line l crosses the x-axis at D and the y-axis at E
4. Calculate the coordinates of the midpoint DE
Triangles, Lines through Triangles and Finding a Point That forms a Right Triangle are investigated.