Surface area of a cube | Mensuration | Assessment | English | Grade 8

Total surface area of a cube with edge 'l' is _______.

• 6 + l²

• 6 /l²

• 6 l²

• 6- l²

Tags

CCSS.6.G.A.4

Lateral surface area of a cube with edge 17 cm is _______.

• 68 cm²

• 289 cm²

• 1156 cm²

• 1734 cm²

Answer explanation

Lateral surface area of a cube = 4 (edge)² = 4 × 17² = 4 × 289 = 1156 cm² So, Option 3 is correct.

Tags

CCSS.6.G.A.4

The edge of a cube whose total surface area is 726 cm² is _______.

• 13 cm

• 17 cm

• 12 cm

• 11 cm

Answer explanation

Total surface area of cube = 6 (edge)² According to the question, we have, 6 (edge)² = 726 cm² (edge)² = 726cm²/6 = 121 cm² edge = √121 cm² = 11 cm So, Option 4 is correct.

Tags

CCSS.6.G.A.4

Samiksha bought a gift for her friend which is packed in a cube shaped box of side 25 cm. She wants to wrap it in a gift paper. How much gift paper is required to wrap the cubical box?

• 3750 cm²

• 3790 cm²

• 2500 cm²

• 625 cm²

Answer explanation

Option 1 is correct as total surface area of cube = 6 (edge)² = 6 × 25² = 3750 cm²

Tags

CCSS.6.G.A.4

A cube of side 16 cm is cut into 4 cm cubes. What is the ratio of the total surface area of the original cube and a cut-out cube?

• 1:4

• 1:16

• 16 : 1

• 4:1

Answer explanation

Total surface area of a cube = 6 l² Total surface area of cube with side 16 cm = 6 l² = 6 (16)² = 6 (256) = 1536 cm² Total surface area of a cut out cube with side 4 cm = 6 l² = 6 (4)² = 6 (16) = 96 cm² Ratio of total surface area of original cube to the total surface area of a cut- out cube = 1536/ 96 = 16/1. Hence option 3 is correct answer.

Tags

CCSS.6.G.A.4

Mina has a cuboidal and a cubical box as shown in figure. She needs to wrap both the boxes with a gift paper. Which box will require more gift paper to wrap?

• Cuboidal box will require more paper

• Cubical box will require more paper

• Both the boxes will require equal amount of paper

• Cannot be determined

Answer explanation

Total surface area of cubical box = 6 l² = 6 (15)² = 6 × 225 = 1350 cm² Total surface area of cuboidal box = 2(lb + bh + hl) = 2 (25 × 5 + 5 × 9 + 9 × 25) = 2( 125 + 45 + 225) = 2(395) = 790 cm² Hence cubical box will require more gift paper by 1350 - 790 = 560 cm² Hence option 2 is correct answer.

Tags

CCSS.6.G.A.4

A rubik's cube is made up of 16 colourful squares on each face of the cube and the side of each colourful square is 2 cm long. The total surface area of the rubik's cube is ________.

• 24 cm²

• 384 cm²

• 256 cm²

• 512 cm²

Answer explanation

Side of one square = 2 cm Area of one square = 2 x 2 = 4 cm² Number of squares on one face of the rubik's cube = 16 Area of one face of the rubik's cube = 16 x area of one square = 16 x 4 = 64 cm² Total surface area of the rubik's cube = 6 x area of one face of the rubik's cube = 6 x 64 = 384 cm² So, option 2 is correct.

Tags

CCSS.6.G.A.4