Question

Acircular ring has across -section as shown .If the outer radias 20 mm and the inner radius 16 mm .Calculate the cross - section area of the ring .

Answer 1

452.45mmm^2

Explanation:

Step one:

Given data

outer radius R= 20mm

inner radius r= 16mm

let us find the area of the outer circle

Area= πR^2

Area= 3.142*20^2

Area= 3.142*400

Area= 1256.8 mm^2

let us find the area of the inner circle

Area= πr^2

Area= 3.142*16^2

Area= 3.142*256

Area= 804.35 mm^2

Hence the area of the section is

Area of outer- Area of inner

=1256.8-804.35

=452.45mmm^2