Question

8. Find the diameter of the circle whose circumference is
(a) 44 cm
(b) 66 cm
(c) 33 cm​

Answer 1

Given

• Circumference of circle -:
• (a) 44 cm
• (b) 66 cm
• (c) 33 cm

To find

• Diameter of the circle

Solution

(a) Circumference = 44 cm

Using formula,

Circumference of circle = 2πr

Where,

• Take π = 22/7
• r = radius of the circle

Substitute the given values,

⟶ 44 = 2 × 22/7 × r

⟶ 44 = 44/7 = r

⟶ (44 × 7)/44 = r

⟶ 7 = r

∴ Radius of the circle = 7 cm

Using formula,

Diameter = 2 × radius

Substitute the values,

⟶ Diameter = 2 × 7

⟶ Diameter = 14 cm

(a) Diameter of the circle is 14 cm when circumference is 44 cm.

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(b) Circumference of the circle = 66 cm

Using formula,

Circumference of circle = 2πr

Where,

• Take π = 22/7
• r = radius of the circle

Substitute the given values,

⟶ 66 = 2 × 22/7 × r

⟶ 66 = 44/7 × r

⟶ (66 × 7)/44 = r

⟶ 10.5 = r

∴ Radius of the circle = 10.5 cm

Using formula,

Diameter = 2 × radius

Substitute the values,

⟶ Diameter = 2 × 10.5

⟶ Diameter = 21 cm

(b) Diameter of the circle is 21 cm when circumference is 66 cm.

________________________________

(c) Circumference = 33 cm

Using formula,

Circumference of circle = 2πr

Where,

• Take π = 22/7
• r = radius of the circle

Substitute the given values,

⟶ 33 = 2 × 22/7 × r

⟶ 33 = 44/7 × r

⟶ (33 × 7)/44 = r

⟶ 5.25 cm

∴ Radius of the circle = 5.25 cm

Using formula,

Diameter = 2 × radius

⟶ Diameter = 2 × 5.25

⟶ Diameter = 10.5 cm

(c) Diameter of the circle is 10.5 cm when circumference is 33 cm.

Answer 2

Question :-

Find the diameter of the circle whose circumference is

(a) 44 cm

(b) 66 cm

(c) 33 cm

Answer :-

• a) Radius = 14cm
• b) Radius = 21cm
• c) Radius = 10.5cm

Solution :-

A) Circumference = 44cm

${:} \longrightarrow \sf\boxed{\bf{Circumference\: of \: Circle \: =\: 2\pi \: r }}$

⇛ 44 = 2 × 22/7 × r

⇛ 44/2 = 22/7 × r

⇛ (22×7)/22 = r

⇛ $\sf \underline \red{\boxed{{7 \: = \: Radius }}}$

★ Diameter = 2 × Radius ★

↦ Diameter = 2 × 7

↦ Diameter = 14cm

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B) Circumference = 66cm

${:} \longrightarrow \sf\boxed{\bf{Circumference\: of \: Circle \: =\: 2\pi \: r }}$

⇛ 66 = 2 × 22/7 × r

⇛ 66/2 = 22/7 × r

⇛ (33×7)/22 = r

⇛ $\sf \underline \red{\boxed{{10.5 \: = \: Radius }}}$

★ Diameter = 2 × Radius ★

↦ Diameter = 2 × 10.5

↦ Diameter = 21cm

━━━━━━━━━━━━━━━━━━━━━━━━━

C) Circumference = 33cm

${:} \longrightarrow \sf\boxed{\bf{Circumference\: of \: Circle \: =\: 2\pi \: r }}$

⇛ 33 = 2 × 22/7 × r

⇛ 33/2 = 22/7 × r

⇛ (16.5×7)/22 = r

⇛$\sf \underline \red{\boxed{{5.25\: = \: Radius }}}$

★ Diameter = 2 × Radius ★

↦ Diameter = 2 × 5.25

↦ Diameter = 10.5cm

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