Question

$\square ABCD$ is the image of $\square A^{\prime }{B}^{\prime }{C}^{\prime }{D}^{\prime }$ under rotation about the origin.The angle of rotation is?

• A. ${135}^o$
• B. ${165}^0$
• C. ${180}^o$
• D. ${80}^o$

Answer 1

The correct option is C ${180}^o$

Angle of rotation is ${180}^{\circ }$

$(-x,y)\to (x,-y)$

$(x,y)\to (-x,-y)$

So,

$A(2,4)\to A^{\prime }(-2,-4)$

$B(1,5)\to B^{\prime }(-1,-5)$

$C(2,4)\to C^{\prime }(-2,-4)$

$D(2,3)\to A^{\prime }(-2,-3)$