Question

a can of Blue Runner Kidney Beans has a surface area of 371 cm^2. its height is 12cm. what is the radius of the circular top? round to the nearest hundredth.

Answer 1

total surface area=area of side+area of top+area of bottom
let r=radius
area of side=height*circumference of circular ends=371*2πr=20πr
area of top and bottom=2*πr^2
20πr+2πr^2=363
2πr^2+20πr-363=0
solve for r using following quadratic formula:
a=2π, b=20π, c=-363
r=4.098 cm

Answer 2

Answer:

4.91 cm

Step-by-step explanation:

Height of can = 12cm

Let the radius of the can be r

Curved Surface area of cylinder = $2 \pi r h$

                                                 = $2 \times \frac{22}{7} r \times 12$  

We are given that a can of Blue Runner Kidney Beans has a surface area of $371 cm^2.$

So, $371=2 \times \frac{22}{7} r \times 12$  

$\frac{371 \times 7}{2 \times 22 \times 12}=r$  

$4.91=r$  

Hence the radius of the circular top is 4.91 cm