Question

two concentric circles of radii 10cm 5cm are drawn. find the length of the chord of the longer circle, which touches the smaller circle?

Answer 1

By Pythagoras' Theorem, the length of the chord of the larger circle touching the smaller circle is,

$\displaystyle\longrightarrow\sf{2x=2\sqrt{10^2-5^2}}$

$\displaystyle\longrightarrow\sf{2x=2\sqrt{100-25}}$

$\displaystyle\longrightarrow\sf{2x=2\sqrt{75}}$

$\displaystyle\longrightarrow\sf{\underline{\underline{2x=10\sqrt3\ cm}}}$