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The lengths of the diagonals of a rhombus are 16 cm and 12 cm. The length of each side of the rhombus is
(a) 8 cm
(b) 9 cm
(c) 10 cm
(d) 12 cm
(c) $10 \mathrm{~cm}$
Let $A B C D$ be a rhombus.
$L$ et $A C$ and $B D$ be the diagonals of the rhombus intersecting at a point $O$. $A C=16 \mathrm{~cm}$
$B D=12 \mathrm{~cm}$
We know that the diagonals of a rhombus bisect each other at right angles.
$\therefore A O=\frac{1}{2} A C$
$=\left(\frac{1}{2} \times 16\right) \mathrm{cm}$
$=8 \mathrm{~cm}$
$B O=\frac{1}{2} B D$
$=\left(\frac{1}{2} \times 12\right) \mathrm{cm}$
$=6 \mathrm{~cm}$
From the right $\Delta A O B$ :
$A B^{2}=A O^{2}+B O^{2}$
$=\left\{(8)^{2}+(6)^{2}\right\} \mathrm{cm}^{2}$
$=(64+36) \mathrm{cm}^{2}$
$=100 \mathrm{~cm}^{2}$
$\Rightarrow A B=\sqrt{100} \mathrm{~cm}$
= 10cm
Hence, the length of the side $A B$ is $10 \mathrm{~cm}$.
Therefore, the length of each side of the rhombus is $10 \mathrm{~cm}$ because all the sides of $a$ rhombus are equal.