ΔABC∼ΔDEF such that ar (ΔABC) = 64 cm2 and ar (ΔDEF)=169cm2. If BC = 4 cm, find EF.
Since triangle ABC is similar to triangle DEF.
Therefore(Area△ABC)(Area△DEF)=BC2EF2
Because the ratio of area of two similar triangles is equal to the ratio of square of their corresponding sides.
64169=42EF
6∗16964
EF = 42.25 cm