100 POINTS!!!!!

Two cylinders are similar with diameters 6 in and 9 in.
a. Find the ratio of the circumference of their bases


b. Find the ratio of the surface areas.



c. Find the ratio of the volumes.

Respuesta :

Answer:

a. Ratio of their circumference = 2:3

b. The ratio of their surface areas = 2:3

c. The ratio of their volume = 4:9

Step-by-step explanation:

Let the cylinders be labelled as A and B respectively.

Diameter of cylinder A = 6 in,

its radius = [tex]\frac{diameter}{2}[/tex]

                = [tex]\frac{6}{2}[/tex] = 3 in

Diameter of cylinder B = 9 in,

its radius = [tex]\frac{diameter}{2}[/tex]

               = [tex]\frac{9}{2}[/tex]  = 4.5 in

Thus,

a. circumference of a circle = 2[tex]\pi[/tex]r

Circumference of cylinder A = 2[tex]\pi[/tex]r

                                               = 2 x [tex]\pi[/tex] x 3

                                            = 6[tex]\pi[/tex] in

Circumference of cylinder B = 2[tex]\pi[/tex]r

                                              = 2 x [tex]\pi[/tex] x 4.5

                                              = 9[tex]\pi[/tex]

Ratio of their circumference = [tex]\frac{circumference of cylinder A}{circumference of cylinder B}[/tex]

                                               = [tex]\frac{6\pi }{9\pi }[/tex]

                                               = 2:3

b. The surface area of a cylinder = 2[tex]\pi[/tex]rh

the surface area of cylinder A = 2[tex]\pi[/tex]rh

                                                  = 6[tex]\pi[/tex]h

the surface area of cylinder B = 2[tex]\pi[/tex]rh

                                                = 9[tex]\pi[/tex]h

The ratio of their surface areas = [tex]\frac{surface area of cylinder A}{surface area of cylinder B}[/tex]

                                                 = [tex]\frac{6\pi h}{9\pi h}[/tex]

                                                 = 2:3

c. Volume of a cylinder = [tex]\pi[/tex][tex]r^{2}[/tex]h

volume of cylinder A = [tex]\pi[/tex][tex]r^{2}[/tex]h

                                = [tex]\pi[/tex] x [tex]3^{2}[/tex] x h

                                = 9[tex]\pi[/tex]h

volume of cylinder b = [tex]\pi[/tex][tex]r^{2}[/tex]h

                                    = [tex]\pi[/tex] x [tex]4.5^{2}[/tex] x h

                                    = 20.25[tex]\pi[/tex]h

The ratio of their volume = [tex]\frac{volume of cylinder A}{volume of cylinder B}[/tex]

                                         = [tex]\frac{9\pi h}{20.25\pi h}[/tex]

                                         = 4:9

d=6in,9in

r=3in,4.5in

circumference:-

[tex]\\ \sf\longmapsto \dfrac{2\pi r_1}{2\pi r_2}[/tex]

[tex]\\ \sf\longmapsto \dfrac{6\pi}{9\pi}[/tex]

[tex]\\ \sf\longmapsto \dfrac{2}{3}[/tex]

[tex]\\ \sf\longmapsto 2:3[/tex]

LSA:-

[tex]\\ \sf\longmapsto \dfrac{2\pi r_1h}{2\pi r_2h}[/tex]

[tex]\\ \sf\longmapsto \dfrac{6}{9}[/tex]

[tex]\\ \sf\longmapsto \dfrac{2}{3}[/tex]

[tex]\\ \sf\longmapsto 2:3[/tex]

TSA

[tex]\\ \sf\longmapsto \dfrac{2\pi r_1(h+r_1)}{2\pi r_2(h+r_2)}[/tex]

[tex]\\ \sf\longmapsto \dfrac{6(h+6)}{9(h+9)}[/tex]

[tex]\\ \sf\longmapsto \dfrac{6h+36}{9h+81}[/tex]

[tex]\\ \sf\longmapsto \dfrac{h(6+36)}{h(9+81)}[/tex]

[tex]\\ \sf\longmapsto \dfrac{42}{90}[/tex]

[tex]\\ \sf\longmapsto \dfrac{7}{15}[/tex]

[tex]\\ \sf\longmapsto 7:15[/tex]

Volume:-

[tex]\\ \sf\longmapsto \dfrac{\pi r_1^2h}{\pi r_2^2h}[/tex]

[tex]\\ \sf\longmapsto \dfrac{3^2}{4.5^2}[/tex]

[tex]\\ \sf\longmapsto \dfrac{9}{20.25}[/tex]

[tex]\\ \sf\longmapsto 4:9[/tex]

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