Question

The diameter of circumcircle of a square is 7 cm. Find the length of side $AB$.

• A. $\frac{7}{2}$ cm
• B. $\frac{\sqrt{7}}{2}$ cm
• C. $\frac{7}{\sqrt{2}}$ cm
• D. $\frac{49}{2}$ cm

Answer 1

The correct option is C $\frac{7}{\sqrt{2}}$ cm

$△ABC$ is right angled triangle.
$AB=BC$ ....($\because \square ABCD$ is a square),
By Pythagoras theorem,

$A{C}^2=A{B}^2+A{C}^{2}2A{B}^2=A{C}^2$

$A{B}^2=\frac{A{C}^2}{2},A{B}^2=\frac{49}{2}$

$AB=\frac{7}{\sqrt{2}}$ cm