Question

pls answer very urgent question if u answer I will mark u as brilliant​

Answer 1

To Find :

• a) Length of arc
• b) perimeter of sector

Solution :

• ∅ = 120°
• Radius = 21cm

Changing degree into radian

= 120 × π/180

= 12 × π/18

= 2π/3 radian

we know that,

• ∅ = l/r

where,

• l = length of arc
• r = Radius

l = ∅r

l = 2π/3× 21

l = 2π × 7

l = 14π

l = 14 × 22/7

l = 2 × 22

l = 44

Hence,

• Length of arc is 44

Perimeter of sector = arc length + Radius + Radius

p = 44 + 21 + 21

p = 44 + 42

p = 86

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Answer 2

Answer:

length of an arc is given by

L= theta*R

where L is length of arc, theta is central angle in radian, and R is radius.

given.

theta = 120° (though degree not mentioned, I am assuming it...fault of question though, might have been grades)

theta = 120*π/180 radian

= 2π/3 radian

R = 21 cm

L = 21*2π/3

L = 14 *π

L = 14*22/7

L = 44 cm

Perimeter of sector = L + 2R

= 44+2*21

= 44 + 42

= 86 cm