In $\triangle A B C, D$ and $E$ are points on sides $A B$ and $A C$, such that $D E$ II $B C$. If $A D=x+3, D B$ $=2 x-3, A E=x+1$ and $E C=2 x-2$, then the value of $x$ is: |
$\frac{4}{5}$ $ \frac{1}{2}$ $ \frac{3}{5}$ $ \frac{1}{5}$ |
$ \frac{3}{5}$ |
Concept Used When two triangles are similar, their corresponding angles are equal and their corresponding sides are proportional. Calculation As DE is parallel to BC and \(\angle\)A is common in both \(\Delta \) ABC and \(\Delta \)ADE So, ABC is similar to ADE So, \(\frac{AB}{AD}\) = \(\frac{AC}{AE}\) = \(\frac{x\;+\;3\;+\;2x\;-\;3}{x\;+\;3}\) = \(\frac{x\;+\;1\;2x\;-\;2}{x\;+\;1}\) = \(\frac{3x}{x\;+\;3}\) = \(\frac{3x\;-\;1}{x\;+\;1}\) = \( { 3x}^{2 } \) + 3x = \( { 3x}^{2 } \) - x + 9x - 3 = 3x = 8x - 3 = 5x = 3 = x = \(\frac{3}{5}\) Therefore, x is \(\frac{3}{5}\) |