Select the correct answer.

The shape of a capsule consists of a cylinder with identical hemispheres on each end. The diameter of the hemispheres is 0.5 inches.

What is the surface area of the capsule? Round your answer to the nearest hundredth.

A. 3.93 in[tex]\(^2\)[/tex]

B. 3.14 in[tex]\(^2\)[/tex]

C. 2.36 in[tex]\(^2\)[/tex]

D. 6.28 in[tex]\(^2\)[/tex]



Answer :

To find the surface area of the capsule, we need to consider the surface area of both the cylindrical part and the two hemispheres at either end. Here's a step-by-step solution to calculate the surface area:

1. Determine the radius:
The diameter of the hemispheres is given as 0.5 inches.
Therefore, the radius [tex]\( r \)[/tex] is:
[tex]\[ r = \frac{\text{diameter}}{2} = \frac{0.5}{2} = 0.25 \text{ inches} \][/tex]

2. Height of the cylindrical part:
The height of the cylindrical part is equal to the diameter of the hemispheres (since it's given that diameter equals the height of the cylindrical part).
[tex]\[ h = 0.5 \text{ inches} \][/tex]

3. Surface area of the cylindrical part:
The formula for the surface area of a cylinder (excluding the top and bottom circles) is:
[tex]\[ A_{\text{cylinder}} = 2\pi r h \][/tex]
Substitute the values of [tex]\( r \)[/tex] and [tex]\( h \)[/tex]:
[tex]\[ A_{\text{cylinder}} = 2\pi \times 0.25 \times 0.5 = \frac{\pi}{2} \text{ square inches} \][/tex]

4. Surface area of the hemispheres:
Each hemisphere has a surface area equal to half of the surface area of a sphere. The surface area of one hemisphere is:
[tex]\[ A_{\text{hemisphere}} = 2\pi r^2 \][/tex]
Since there are two hemispheres, we multiply this by 2:
[tex]\[ A_{\text{hemispheres}} = 2 \times 2\pi r^2 = 4\pi r^2 \][/tex]
Substitute the value of [tex]\( r \)[/tex]:
[tex]\[ A_{\text{hemispheres}} = 4\pi \times (0.25)^2 = 4\pi \times 0.0625 = 0.25\pi \text{ square inches} \][/tex]

5. Total surface area of the capsule:
The total surface area [tex]\( A_{\text{capsule}} \)[/tex] is the sum of the surface area of the cylindrical part and the surface area of the hemispheres:
[tex]\[ A_{\text{capsule}} = A_{\text{cylinder}} + A_{\text{hemispheres}} = \frac{\pi}{2} + 0.25\pi = 0.5\pi + 0.25\pi = 0.75\pi \text{ square inches} \][/tex]

6. Numerical calculation:
Convert the result to a numerical value (since [tex]\(\pi \approx 3.1416\)[/tex]):
[tex]\[ A_{\text{capsule}} = 0.75 \times 3.1416 \approx 2.3562 \text{ square inches} \][/tex]

7. Rounding to the nearest hundredth:
The value approximately 2.3562 rounded to the nearest hundredth is 2.36.

Thus, the surface area of the capsule is:
[tex]\[ \boxed{2.36 \text{ in}^2} \][/tex]

Therefore, the correct answer is:
C. 2.36 in [tex]$^2$[/tex]