Answer:
Q3. 67.24 sq. ft.
Q4. 22582.88 sq. cm.
Q6. 115 sq. cm.
Q10. 240 sq. in.
Explanation:
Q3.
The formula of a lateral area of a cube with side s:
![LA=4s^2](https://img.qammunity.org/2020/formulas/mathematics/high-school/dkhfc7kvsn5wfut73cvhqcb5xi5j4p6114.png)
We have s = 4.1 ft.
Substitute:
![LA=4(4.1^2)=4(16.81)=67.24\ ft^2](https://img.qammunity.org/2020/formulas/mathematics/high-school/w8demhcvxjepj0lpc2pj73fsqijkpryp70.png)
Q4.
The formula of a surface area if a cylinder:
![SA=2\pi r^2+2\pi rH](https://img.qammunity.org/2020/formulas/mathematics/high-school/tkf1e3bf8865ffhw31n6zf29wt3hwag80c.png)
r - radius
H - height
We have 2r = 62 cm → r = 31 cm, H = 85 cm.
Substitute:
![SA=2\pi(31^2)+2\pi(31)(85)=2\pi(961)+5270\pi=1922\pi+5270\pi=7192\pi\ cm^2](https://img.qammunity.org/2020/formulas/mathematics/high-school/nloptgf797au8hc6zl7z32er4i22vqnco4.png)
![\pi\approx3.14\to SA\approx(7192)(3.14)=22582.88\ cm^2](https://img.qammunity.org/2020/formulas/mathematics/high-school/yvlzkyj0gffbfa9gnoiy07zkabnoa3n8ch.png)
Q6.
The surface area of a square piramid is
base - square
lateral sides - four triangles
The formula of an area of a square with sides s:
![A=s^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7qjqar9k4ynqdm5a89kdy8hazgw5jtmal8.png)
The formula of an area of a triangle with base b and height h:
![A=(bh)/(2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ldsjq5pl6s8nfwkzzwkdtmhxkudpyw69zw.png)
We have s = 5 cm, b = s = 5 cm, h = 9 cm.
Substitute:
![A_(\square)=5^2=25\ cm^2\\\\A_(\triangle)=((5)(9))/(2)=(45)/(2)=22.5\ cm^2](https://img.qammunity.org/2020/formulas/mathematics/high-school/ncxjlh98foloyf3jbucy6y2so6rrg4u82x.png)
The surface area:
![SA=A_(\square)+4A_(\triangle)\\\\SA=25+4(22.5)=25+90=115\ cm^2](https://img.qammunity.org/2020/formulas/mathematics/high-school/j3ev9o2erheuwejmu1gyx9ln4k7tvwidre.png)
Q10.
The lateral sides are two pairs of rectangles.
The formula of an area of a rectangle:
![A=l\cdot w](https://img.qammunity.org/2020/formulas/mathematics/high-school/k7d40bp01sbcfukg0hmjsujknrdkjgp96e.png)
l - length
w - width
We have the rectangles:
5 in × 10 in and 7 in × 10 in
Substitute:
![A_1=(5)(10)=50\ in^2\\\\A_2=(7)(10)=70\ in^2](https://img.qammunity.org/2020/formulas/mathematics/high-school/tiodwfjqvsq89uvttz4eyvlc3ooa8j5kay.png)
The lateral area:
![LA=2A_1+2A_2\\\\LA=2(50)+2(70)=100+140=240\ in^2](https://img.qammunity.org/2020/formulas/mathematics/high-school/qh378nxohq9zj0kszvc88nl5v9qektqckb.png)