Question

A circular ring shaped copper plate has 269.5
sq cm of plate. If the outer diameter of the
ring is 28 cm, what is its inner diameter ?
​

Answer 1

Answer:

4.5 cm

Step-by-step explanation:

Y

CM

=

m

1

+m

2

m

1

x

1

+m

2

x

2

0=

m

1

+m

2

ρπ(10.5)

2

t×3.5+ρπ(14

2

−10.5

2

)tx

2

Here πr

2

t is volume and mass is written in terms of density times volume, where ρ is the density of plate material and t is the thickness of the plate.

x2

=

14

2

−10.5

2

10.5

2

×3.5

x

2

=4.5 cm