In the given question we have been asked to calculate the ratio of two sides of a triangle and the length of a side DE by using the properties of similarities
Rajan@2021Guru
In the figure (i) given below if DE∥BG,AD=3 cm,BD=4 cm and BC=5 cm. Find (i) AE:EC (ii) DE
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From the figure,
DE∥BG,AD=3cm,BD=4cm and BC=5cm
(i) AE:EC
So, AD/BD=AE/EC
AE/EC=AD/BD
AE/EC=3/4
AE:EC=3:4
(ii)consider △ADE and △ABC
∠D=∠B
∠E=∠C
Therefore, △ADE∼△ABC
Then, DE/BC=AD/AB
DE/5=3/(3+4)
DE/5=3/7
DE=(3×5)/7
DE=15/7