Question

1. The radius of the circular base of a cylinder tank is 0.7 m and its height is 5 m. What is

its surface area??

A. 20.5572 sqm
B. 22.5072 sqm
C. 25.0572 sqm
D. 27.0552

2. An ice cream cone has a radius of 7 cm and a slant height of 10 cm. What is its surface
area?

A. 337.66 sq cm
B.373.66 sq cm
C.376.36 sq cm
D. 376.66 sq cm


help, it's just 1-3 :( with solution please :(

3. A cubical wooden box has a surface area of 600 square cm. What is the measurement
of each
edge?

B. 6 cm
C. 10 cm
A. 5 cm
D. 100 cm
​

Answer 1

C)

B)

C)

Explanation:

Question-1:

recall the surface area formula of cylinder

`\displaystyle A _(S) = 2\pi r(h + r)`

given that,h=5 and r=0.7

substitute:

`\displaystyle A _(S) = 2\pi (0.7)(5 + 0.7)`

simplify parentheses:

`\displaystyle A _(S) = 2\pi (0.7)(5 .7)`

simplify multiplication:

`\displaystyle A _(S) =25.0572 sqm`

hence, our answer is C

Question-2:

remember the surface area formula of cone

`\displaystyle A _(S) = \pi r(r + s)`

given that,r=7 and s=10

substitute:

`\displaystyle A _(S) = \pi (7)(7+ 10)`

simplify parentheses:

`\displaystyle A _(S) = \pi (7)(17)`

simplify multiplication:

`\displaystyle A _(S) =373.66sqcm`

hence, our answer is B

Question-3:

now for the question-3 we need a little bit understanding

remember the surface area formula of cube

`\displaystyle A _(S) =6 {a}^(2)`

we are given that,
`A_S=600` Thus

substitute:

`\displaystyle 6 {a}^(2) = 600`

divide both sides by 6:

`\displaystyle {a}^(2) = 100`

square root both sides:

`\displaystyle {a}^{} = 10`

hence, the measurement of each

edge is 10 cm therefore our answer is C)