Question

(please show your answer. thank you)

Answer 1

The correct option is: A. 80 cm³

Explanation

Diameter of the coin, $d= 2.0$ cm.

So, the radius, $r= \frac{d}{2} = \frac{2.0}{2} = 1.0$ cm.

As the coin is circular, so..

Area of each circular surface, $A= \pi r^2 = \pi (1.0)^2 = \pi$ cm²

Now for finding the amount of plastic for making each coin, we will find the Volume of each coin first.

As the thickness ($h$) of the coin is 0.5 cm, so Volume of each coin,

$V= A*h \\\\= \pi*0.5 \\\\= 3.14159... * 0.5 \\\\ = 1.5707963... cm^3$

As you need to make a batch of 50 coins, so the total volume of 50 coins $= (1.5707963...*50 )= 78.53981... = 80$ [Rounded up to the nearest multiple of 10 cm³]

So, the amount of plastic you will need for making a batch of 50 coins is 80 cubic centimeter.