The ratio of the corresponding sides of two similar triangles is $3:4$. The ratio of their areas?

O is the point of intersection of two equal chords AB and CD such that OB = OD, then triangles OAC and ODB are

$∆ABC$ and $∆DEF$ are similar. Also $\angle A=\angle D$ and $\angle B=\angle E$. If $4AB=DE$ and $BC=12$ $cm$, then $EF$ is equal to

The segment $XY$ is parallel to side $AC$ and the segment $XY$ divides the triangle in two equal area, then $\frac{AX}{AB}$ is

In a triangle ABC, D and E are the midpoints of AB and AC and if AB = 12 cm, BC = 9 cm and AC =10 cm, then the measure of DE is: