Question

In a square, $ABCD$, $AB=y+9$ & $BC=-2y+18$. So, length of $CD$ is

• A. $9$
• B. $3$
• C. $12$
• D. None

Answer 1

The correct option is C $12$

Given, $AB=y+9$ and $BC=-2y+18$

We need to find value of $CD$

All sides of a square are equal in length.
Therefore, $AB=BC=CD=AD$
$\Rightarrow y+a=-2y+18$

$\Rightarrow 3y=9$

$\Rightarrow y=3$
Therefore, length of $CD=3+9=12$.