Question

In the figure, $ABCD$ is a rectangle, $△CEF$ is an equilateral triangle. Find $x$.

• A. ${25}^o$
• B. ${30}^o$
• C. ${20}^o$
• D. ${50}^o$

Answer 1

The correct option is A ${25}^o$

It is given that, $ABCD$ is a rectangle
$\therefore \angle ADC={90}^o$
In $△ADC$, we have

$\angle DAC+\angle ADC+\angle DCA={180}^o$ (Angle sum property)
$\Rightarrow {65}^o+{90}^o+x={180}^o$

$\Rightarrow x={25}^o$