Question

Please help me with this 4 question​

Answer 1

i) c. 1,08,00,000 cm³

ii) c. 1687.5 cm³

iii) b. 6400

Q.3) Suface area of cube is 294 cm².

Step-by-step Step-by-step explanation:

Q.2. 12 men are building a wall which is 8 m long, 6 m high and 22.5 cm thick using bricks. On this basis answer the following.

i. Find the volume of the cuboidal wall.

• Length (l) = 800 m
• Breadth (b) = 6600 m
• Height (h) = 22.5 cm

Substituting all the given values in the formula to find volume of cuboidal wall :

`\begin{gathered}\qquad{\longrightarrow{\sf{V = LBH}}} \\ \\ \qquad{\longrightarrow{\sf{V = L * B * H}}} \\ \\ \qquad{\longrightarrow{\sf{V = 800 * 600 * 22.5}}} \\ \\ \qquad{\longrightarrow{\sf{V = 480000 * 22.5}}} \\ \\ \qquad{\longrightarrow{\sf{\underline{\underline{\red{V = 1,08,00,000 \: {cm}^(3)}}}}}} \end{gathered}`

Hence, the volume of cuboidal wall is 1,08,00,000 cm³.

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ii. If the dimension of each brick is 25 cm × 11.25 cm × 6 cm, then find the volume of the brick.

• Length (l) = 25 cm
• Breadth (b) = 11.25 m
• Height (h) = 6 cm

Substituting all the given values in the formula to find the volume of cuboidal brick :

`\begin{gathered}\qquad{\longrightarrow{\sf{V = LBH}}} \\ \\ \qquad{\longrightarrow{\sf{V = L * B * H}}} \\ \\ \qquad{\longrightarrow{\sf{V = 25 * 11.25* 6}}} \\ \\ \qquad{\longrightarrow{\sf{V = 281.25* 6}}} \\ \\ \qquad{\longrightarrow{\sf{\underline{\underline{\pink{V = 1687.5 \: {cm}^(3)}}}}}} \end{gathered}`

Hence, the volume of cuboidal brick is 1687.5 cm³.

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iii. How many bricks will be required to construct the cuboidal wall.

• Volume of wall = 10800000 cm³
• Volume of brick = 1687.5 cm³

Substituting all the given values in the formula to find the number of bricks :

`\begin{gathered} \quad{\longrightarrow{\sf{No. \: of \: bricks = (Volume \:of \: wall)/(Volume \: of \: brick)}}}\\ \\ \quad{\longrightarrow\sf{No.\: of \: bricks = (10800000)/(1687.5)}} \\ \\ \quad{\longrightarrow{\sf{No. \: of \: bricks = \cancel{(10800000)/(1687.5)}}}} \\ \\ \quad{\longrightarrow{\sf{\underline{\underline{\purple{No. \: of \: bricks = 6400}}}}}}\end{gathered}`

Hence, 6400 bricks will be required to construct the cuboidal wall.

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Q.3 The volume of a cube is 343 cm³. Fibd its surface area.

• Surface area = 294 cm²

For clear understanding please check the given attachment.

`\rule{300}{2.5}`