Question

A right cylinder has a radius of r inches and height of 2r inches.

Answer 1

Answer:

its 4, 2, 6 on ed

Step-by-step explanation:

Answer 2

Answer:

Part a) The lateral area is $4r^{2} \pi \ in^{2}$

Part b) The area of the two bases together is $2r^{2} \pi\ in^{2}$

Part c) The surface area is $6r^{2} \pi\ in^{2}$

Step-by-step explanation:

we know that

The surface area of a right cylinder is equal to

$SA=LA+2B$

where

LA is the lateral area

B is the area of the base of cylinder

we have

$r=r\ in$

$h=2r\ in$

Part a) Find the lateral area

The lateral area is equal to

$LA=2\pi rh$

substitute the values

$LA=2\pi r(2r)$

$LA=4r^{2} \pi\ in^{2}$

Part b) Find the area of the two bases together

The area of the  base B is equal to

$B=r^{2} \pi\ in^{2}$

so

the area of the two bases together is

$2B=2r^{2} \pi\ in^{2}$

Part c) Find the surface area of the cylinder

$SA=LA+2B$

we have

$LA=4r^{2} \pi\ in^{2}$

$2B=2r^{2} \pi\ in^{2}$

substitute

$SA=4r^{2} \pi+2r^{2} \pi=6r^{2} \pi\ in^{2}$