Area of a triangles - same base and same parallels
1)If two triangles are having same base 4 cm and their area is 12 cm² and lying between the same parallel lines, what will be the height?

2)If a triangle and a parallelogram are on the same base and between the same parallels, then what will be area of triangle ?

3)Triangles ABC and DBC are on the same base BC and with vertices A and D on opposite sides of BC such that ar (∆ABC) = ar (∆DBC). What is the relation between their altitudes

4)D and E are points on sides AB and AC respectively of ∆ABC, such that ar(∆DBC) = ar(∆EBC). Are lines DE and BC parallel to each other?