Question

I need help on 8 and 9 i don’t know how to do them lol

Answer 1

8) h = 30

Explanation:

Answer 2

8) h = 30

r = 16

l= 34

Surface Area= 2514.28

Volume= 8045.71

9) r = 12

h = 2

l = 5/2

Surface Area= 908.08

Volume= 298.42

Explanation:

8)

h = 30

r = 16

l=?

Since its is right angled triangle, using pythogras theorem we can find the length of cone

l^2 = h^2 + r^2

l^2 = (30)^2 + (16)^2

l^2 = 900 + 256

l^2 = 1156

Taking square root on both sides

√l^2 = √1156

l = 34

Surface Area =
`[tex]\pi r(r+√(h^2+r^2) )`[/tex]

π = 22/7, r = 16, h=30

Surface Area =
`=(22)/(7)* 16(16+√((30)^2+(16)^2))\\=(22)/(7)* 16(16+34)\\=(22)/(7)* 800\\=2514.28`

Volume =
`\pi r^2(h)/(3)`

π = 22/7, r = 16, h= 30

Volume =
`(22)/(7) * (16)^2 *(30)/(3)\\=(22)/(7) * 256 *10\\= 8045.71`

9)

r = ?

h = 2

l = 5/2

Since its is right angled triangle, using pythogras theorem we can find the radius of cone

l^2 = h^2 + r^2

(5/2)^2 = (30)^2 + (r)^2

25/4 = 900 + r^2

r^2 = 900 * 4/25

Taking square root on both sides

√r^2 = √144

r = 12

Surface Area =
`[tex]\pi r(r+√(h^2+r^2) )`[/tex]

π = 3.14, r = 12, h=2

Surface Area =
`=3.14* 12(12+√((12)^2+(2)^2))\\=3.14* 12(12+12.1)\\=3.14* 289.2\\=908.08`

Volume =
`\pi r^2(h)/(3)`

π = 22/7, r = 12, h= 2

Volume =
`3.14 * (12)^2 *(2)/(3)\\=3.14 * 144 *0.66\\= 298.42`