Question

The surface area of a cube whose edge is 21 cm ​

Answer 1

Answer:

surface area = 6a^2

a=21cm

6×21^2 = 2646cm2

Answer 2

..Question..

Find the surface area of a cube whose edge is 21 cm.

..Answer..

♧︎︎︎ Given ,

ㅤㅤㅤㅤ➪ side of the cube = 21 cm

ㅤㅤㅤㅤ➪ side of the cube = a ----- ( 1 )

•°• Surface area of the cube ☞︎︎︎

ㅤㅤ➪ 6 a ²

ㅤㅤ➪ 6 × ( 21 )² [ from ( 1 ) ]

ㅤㅤ➪ 6 × ( 20 + 1 )²

ㅤㅤ➪ 6 × ( 20² + 2×20×1 + 1² )

ㅤㅤ➪ 6 × ( 400 + 40 + 1 )

ㅤㅤ➪ ( 6 × 400 ) + ( 6 × 41 )

ㅤㅤ➪ 2400 + 246

ㅤㅤ➪ 2646 ㅤㅤㅤㅤAns....

•°• Surface area of the cube = 2646 cm²

_____________________

Give a look here ,

☯︎ C.S.A of Cylinder

ㅤㅤ➪ 2 π r h

☯︎ Total Surface area of Cylinder

ㅤㅤ➪ 2 π r ( r + h )

☯︎ Circumference of circle

ㅤㅤ➪ 2 π r

☯︎ Area of square

ㅤㅤ➪ π r²

☯︎ perimeter of square

ㅤㅤ➪ 4 s

☯︎ Area of square

ㅤㅤ➪ s²

☯︎ Perimeter of rectangle

ㅤㅤ➪ 2 ( l + b )

☯︎ Area of Rectangle

ㅤㅤ➪ l × b

ㅤㅤㅤ꧁ ʙʀᴀɪɴʟʏ×ᴋɪᴋɪ ꧂

ㅤㅤ