Question

Reposted question. pls tell me what i did wrong in this question

Answer 1

Answer:

total SA = 622.725mm^2

Step-by-step explanation:

we are trying to find the surface area of this structure

we can start by breaking this structure into three pieces.

(surface area of the left hemisphere)+(surface area of the right hemisphere)+(surface area of the right cylinder inbetween those 2 hemispheres)

1. surface area of the hemisphere.

surface area of a hemisphere is 4$\pi$$r^2$

d = 8.4mm so r = 4.2mm.

surface area = $4\pi (4.2)^2 = 221.670mm^2$

we need to take the half of 221.607 since it is half the hemisphere which is 221.670/2 = 110.835mm^2

we have two half hemisphere on the left and right so the tottal surface area of both the half hemisphere is 110.835x2 = 221.670mm^2

2. surface area of the right cylinder.

SA of right cylinder = $2\pi rh$

$2\pi (4.2)(15.2) = 401.118mm^2$

So the entire surface area is.

(surface area of both the half hemisphere + surface area of the right cylinder)

221.607+401.118 = 622.725mm^2