Math, asked by lungsi8056149251, 9 months ago

6. if the perimeter of a semicircle is 36 cm then its radius is
7. The radius of a sphere whose surface area is 154 cm is
8. The number of cubes of side 2 cm which can be cut from a cube of side 6 cm​

Answers

Answered by BrainlyTornado
27

ANSWER 1:

  • Radius of the semicircle = 11.46 cm.

GIVEN:

  • Perimeter of the semicircle is 36 cm.

TO FIND:

  • Radius of the semicircle.

EXPLANATION:

Perimeter of semicicle = πr units.

Perimeter of the semicircle = 36 cm.

π r = 36

r = 36 / 3.14

r = 11.46 cm

HENCE THE THE RADIUS OF THE SEMICIRCLE = 11.46 cm.

ANSWER 2:

  • Radius of the sphere is 3.5 cm.

GIVEN:

  • Surface area of the sphere is 154 cm².

TO FIND:

  • Radius of the sphere.

EXPLANATION:

Surface area of the sphere = 4 π r² sq. units.

Surface area of the sphere = 154 cm².

4 π r² = 154

4 × 22 / 7 × r = 154

r² = 7 × 7 / 4

r² = 49/4

r = 7/2

r = 3.5 cm

HENCE THE RADIUS OF THE SPHERE = 3.5 cm.

ANSWER 3:

  • 27 cubes of side 2 cm can be cut off from the cube of side 6 cm.

GIVEN:

  • Cubes of side 2 cm are cut from a cube of side 6 cm.

TO FIND:

  • Number of cubes which can be cut.

EXPLANATION:

Volume of cube = a³

Let volume of larger cube be a³ and the volume of smaller cube (a')³

Volume of larger cube (a³) = 6³

Volume of smaller cube [ (a')³ ] = 2³

a³ = (a')³ × n

6 × 6 × 6 = 2 × 2 × 2 × n

n = 3 × 3 × 3

n = 27

HENCE 27 CUBES CAN BE CUT OFF.

Answered by Anonymous
20

Answer 6.

Perimeter of semicircle = 1/2 × Circumference of circle

= 1/2 × 2 πr

Perimeter of semicircle = πr

→ 36 = 22/7 × r

→ 36(7)/22 = r

→ 11.45 = r

Hence the radius of the semicircle is 11.45 cm.

Answer 7.

Area of sphere = 4πr²

Substitute the known values in the above formula,

→ 154 = 4 × 22/7 × r²

→ 154(7)/22(4) = r²

→ 12.25 = r²

→ 3.5 = r

Hence, the radius of the sphere is 3.5 cm.

Answer 8.

Volume of cube of 6 cm = Volume of cube of 2 cm × n

→ 6 × 6 × 6 = 2 × 2 × 2 × n

→ 216/8 = n

→ 27

Hence, the number of cubes is 27.

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