Question

please it's urgent . i need 5no. solution ​

Answer 1

EXPLANATION:-

(a) Find the area of shaded region

Area of shaded region is =Area of bigger circle - Area of smaller circle

Area of bigger circle =$\sf\;\pi R^2$

Area of smaller circle=$\sf;\pi r^2$

$==>\sf\;\pi R^2-\sf;\pi r^2\\\\==>\pi (R^2-r^2)$

(b) IF r=12 cm and r=4 cm calculate it's actual area:-

As we calculated in the above question that the area of shaded region :-$\sf\;\\\\==>\pi (R^2-r^2)$

Let's put the data in the formula:-

$\sf\;Area\;of\;shaded\;region\;\sf\;\==>\pi (R^2-r^2)\\\\R=14\;cm\;and\;r=4\;cm :-\\\\==>\pi (14^2-4^2)\\\==>\pi (196-16)\\\==>\pi( 180)$

Hence the area of shaded region is $\sf\;180\pi$