Question

An iron washer is made by cutting out from a circular plate of radius $10cm$, a concentric circular plate of radius $6cm$. The area of the face of the washer nearly is (use $\pi =3.14$)

• A. 201 $c{m}^2$
• B. 206 $c{m}^2$
• C. 200 $c{m}^2$
• D. 204 $c{m}^2$

Answer 1

Answer: (A)

201 $c{m}^2$

R=10 cm, r=6 cm
Area of washer $=\pi (R+r)(R-r)$
$=3.14\times 16\times 4$
$=200.96c{m}^2=201c{m}^2$